DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 2/4/2026 has been entered.
Response to Arguments
Applicant's arguments filed on 2/4/2026 have been fully considered but they are not persuasive. The examiner has thoroughly reviewed Applicant’s amendment and arguments but firmly believes that the cited references reasonably and properly meet the claimed limitations as rejected.
1). Applicant’s argument – Suzuki is directed to a unidirectional optical power monitor that provides excellent uni-directionality. See, e.g., Suzuki 57. Thus, unlike the optical power monitor of claims 1-3, 5, and 12 which generate measurements for optical signals propagating in both directions, Suzukiis concerned with measuring an optical signal propagating in a first direction and received via an input optical fiber 3 without measuring an optical signal propagating in a second direction and received via an output optical fiber 4. To this end, Suzuki discloses a sleeve 9 having a circular hole 91 that receives a free-space optical signal from the input optical fiber 3 and a free-space optical signal from the output optical fiber 4. The sleeve 9, however, is structured such that only the free-space optical signal from the input optical fiber 3 reaches the photodiode 10. Thus, Suzuki does not disclose, among other things, a first and a second housing aperture through which a first free-space optical tap beam and a second free-space optical tap beam respectively passes. Moreover, given the unidirectional objective of Suzuki, it is not obvious to combine/modify Liu'205, Liu'582, and/or Pacala in a manner that arrives at such aspects of claims 1-3, 5, and 12.
Examiner’s response – In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
In Figure 7 of Suzuki et al, only one photo-detector (85) is used, and “The center line of the GRIN lens is disposed, shifted from that of the photo-detector 85 (equivalent to a photodiode)”, and then one of pair of free-space optical tap beams is sent to the photo-detector 85; and, the power of the incoming light from the input optical fiber 82 (port 2) is not measured ([0010], “The light, which has transmitted through the dielectric mirror, does not enter the photo-detector 85 but is discharged to the outside because the optical axis (center line) of GRIN lens is shifted from the optical axis (center line) of the photo-detector 85. Accordingly, the intensity of the incoming light from the output optical fiber 82 (port 2) is impossible to measure. Such a series of optical paths are indicated by broken-line arrows. In other words, there is used an optical power monitor which has uni-directionality, that is, the following phenomenon: the intensity of the incoming light from the input optical fiber 81 (port 1) is possible to measure and the intensity of the incoming light from the output optical fiber 82 (port 2) is not possible to measure”).
However, Liu ‘205 and Liu ‘258 discloses that two photodetectors can be used to measure the bidirectional optical powers and Liu ‘205 indicates that multi-element detector can be used to detect the components from IN 1 and IN 2 separately (for Figure 3); also for the embodiment shown in Figure 6, Suzuki et al discloses “an example of a bi-directional optical power monitor miniaturized for easy handling. FIG. 6 is a structure of the disclosed monitor. A multi-capillary glass ferrule 53 (equivalent to a pig tail fiber) having two optical fibers 51, 52, respectively (an input optical fiber 51 and an output optical fiber 52, respectively) and GRIN (Gradient Index) lens 54 are made to face each other through an air gap 55 with a predetermined length. On an end surface of the GRIN lens, a filter 56 (equivalent to a tap film) is provided to permit the light passing through the GRIN lens to reflect and penetrate. The light transmitting through the filter passes through an air gap 57 and is converted into an electric signal by a photon detector 58 (corresponding to a photodiode) to measure the intensity of the light inputted into the optical fiber. The multi-capillary glass ferrule 53 and the GRIN lens 54 are retained with glass tubes 60, 61. Because both the two optical fibers 51, 52 permits light inputs and outputs, this apparatus may be called a bi-directional optical power monitor.” That is, as long as the two light beams (solid-line and broken-line) can impinge on photodetector(s), a bi-directional power monitor can be realized.
Then, it is obvious to one skilled in the art that another photodetector can be installed in the system of Figure 7 of Suzuki et al so that the system disclosed by Suzuki et al can be used for bi-directional power monitoring. Following figure is the combination of Liu ‘205 and Liu ‘258 and Suzuki et al.
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Therefore, the combination of Liu'205, Liu'582, and Suzuki teaches/suggests to “generate(s) measurements for optical signals propagating in both directions”. Also, each photodetector 85 has its own housing.
2). Applicant’s argument – The Applicant respectfully points out that Suzuki FIGS. 6 and 7 depict conventional power monitors. In particular, Suzuki FIG. 6 depicts a bi-directional optical power monitor miniaturized for easy handling, whereas FIG. 7 depicts an optical power monitor having uni-directionality. See, e.g., Suzuki 7 and 9. Suzuki further notes that FIG. 7 fails to depict a sleeve to position the GRIN lens and photodiode. See, Suzuki 12. The Applicant respectfully submits that the remainder of Suzuki addresses how to position a GRIN lens and photodiode so as to achieve a compact uni-directional power monitor. See, e.g., Suzuki 15. Given such purpose/focus of Suzuki, one or ordinary skill in the art would not find it obvious to add a second photodiode to the conventional embodiment of FIG. 7 so as to achieve a bi-directional optical power monitor. In particular, the proposed modification to the Suzuki power monitor would render the resulting Suzuki device unsatisfactory for its intended purpose and/or would materially change the principle of operation of the disclose Suzuki power monitor. See, e.g., MPEP 2143.01(V) and 2143.01 (VI).
In short, Suzuki's objective is to "obtain a small-sized uni-directional power monitor with an excellent directional characteristic having an input optical fiber and an output optical fiber, in which an optical sensitivity for optical signal incident from the input optical fiber is superior, but an optical sensitivity for optical signal coming from the output optical fiber is low." See, Suzuki 15. Further, Suzuki 30 states "It is necessary for the unidirectional optical power monitor of the present invention that only a light coming from an optical fiber and transmitting through the tap film is measured by a photodiode, while a light coming from the other optical fiber and transmitting through the tap film is not measured by the photodiode." See, also Suzuki 32, 57, 58, 74. However, the Final Office Action advocates modifying the Suzuki power monitor in a manner that fails to achieve the very purpose for which the Suzuki power monitor was designed. As such, one skilled in the art would not find it obvious, in view of Liu'205, Liu'582, and/or Pacala to modify Suzukithe proposed manner.
Examiner’s response – Regarding Applicant’s statement “Suzuki further notes that FIG. 7 fails to depict a sleeve to position the GRIN lens and photodiode”, what is stated by Suzuki in para. [0012] is “a positional relationship between the optical axis of the GRIN lens and the optical axis of the photodiode is described, however, a detailed structure of the optical path between the GRIN lens and the photodiode is not described. The unidirectional optical power monitor requires to position and fix the GRIN lens and the photodiode with a sleeve or the like”; it is obvious to one skilled in the art that a sleeve is used to hold the GRIN lens and photodiode etc.
Regarding Applicant’s statement “the proposed modification to the Suzuki power monitor would render the resulting Suzuki device unsatisfactory for its intended purpose and/or would materially change the principle of operation of the disclose Suzuki power monitor”, as disclosed by Suzuki, when only one photodetector (85) is used, “The light, which has transmitted through the dielectric mirror, does not enter the photo-detector 85 but is discharged to the outside because the optical axis (center line) of GRIN lens is shifted from the optical axis (center line) of the photo-detector 85. Accordingly, the intensity of the incoming light from the output optical fiber 82 (port 2) is impossible to measure. Such a series of optical paths are indicated by broken-line arrows. In other words, there is used an optical power monitor which has uni-directionality, that is, the following phenomenon: the intensity of the incoming light from the input optical fiber 81 (port 1) is possible to measure and the intensity of the incoming light from the output optical fiber 82 (port 2) is not possible to measure” ([0010]). Because of the using of the GRIN lens (83) and the proper distance (“at least a certain distance”) between the GRIN lens and the photodetector, the two optical beams (solid-line and broken-line) from different directions are separated, the light from fiber 81 (solid-line) will impinge on photodetector 85, but light from fiber 82 (broken-line) will not impinge on the photodetector (85; “impossible to measure”); that is the light from fiber 81 (solid-line) and the light from fiber 82 (broken-line) are independently transmitted; and then, when a second photodetector is used to measure the intensity of the light from the fiber 82 (broken-line), the measurement of the intensity of light from the fiber 81 will not be affected since the two photodetectors measure different light beams independently and separately. And the addition of an additional photodiode to measure the intensity of another beam will not affect the measure of the current existent photodiode (e.g., 85) that measure different light beam. Therefore, applicant’s argument “the proposed modification to the Suzuki power monitor would render the resulting Suzuki device unsatisfactory for its intended purpose and/or would materially change the principle of operation of the disclose Suzuki power monitor” is incorrect and not persuasive. And, the addition of another photodetector enhances Suzuki’s system (or another advantage): bi-directional monitoring.
3). Applicant’s argument – Furthermore, while Liu'205, Liu'582, and Suzuki are each directed to devices that monitor optical power of an optical signal propagating through an optical fiber, Pacala is not. In particular, Pacala is directed to optical imagers and optical transmitters used with such optical imagers. Namely, Pacala is directed to an optical imaging system that is essentially a camera that captures images using a wide field-of-view. In other words, Pacala is not concerned with monitoring light propagating through an optical fiber (i.e., light having a very narrow range of angles and a very narrow spatial origin) but capturing free-space light from a wide field-of-view (i.e., light having a very wide range of angles and a very wide range of spatial origin). As such, due to such wide variance in angle and origin, among other things, Pacala explains that micro-optical receivers arrayed adjacent to each are susceptible to crosstalk. See, e.g., 7.
In particular, due to the nature of the camera design, light is inevitably spread across multiple micro-optical receivers, thus resulting in crosstalk between such micro- optical receivers. To reduce such crosstalk, the micro-optical receivers include several structures to reduce crosstalk between receiver channels. See, e.g., Pacala 163. Despite the disclosed arrangement of micro-optical receivers, their respective apertures nonetheless receive stray light. Accordingly, one skilled in the art would not find it obvious to modify Liu'205, Liu'582, and Suzuki in a manner that arrives at the arrangement set forth in claims 1-3, 5, and 12 based on the proffered reason of reducing crosstalk as such arrangement does not address the crosstalk concerns of Pacala.
Examiner’s response – First, regarding In response to applicant's argument “Pacala is not concerned with monitoring light propagating through an optical fiber (i.e., light having a very narrow range of angles and a very narrow spatial origin) but capturing free-space light from a wide field-of-view (i.e., light having a very wide range of angles and a very wide range of spatial origin)”, it has been held that a prior art reference must either be in the field of the inventor’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned, in order to be relied upon as a basis for rejection of the claimed invention. See In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992). In this case, both the claimed invention and Pacala use optical receiver to detect optical beams, and both claimed invention and Pacala use the housings to reduce cross-talk between the signals impinging a pair of photodiodes. Therefore, reference Pacala is in the field of the inventor’s endeavor and is reasonably pertinent to the particular problem with which the inventor was concerned: reducing reduce cross-talk between two photodiodes.
Second, regarding applicant’s argument “Pacala is not concerned with monitoring light propagating through an optical fiber (i.e., light having a very narrow range of angles and a very narrow spatial origin) but capturing free-space light from a wide field-of-view”, as disclosed by Applicant and indicated in the claims, the two photodiodes provide, based on the first and second “free-space optical tap beams”, measurements of optical power for signals. As shown in Applicant’s Figures 1-4, after the reflective element 34, the two optical beams O1f and O2f are “propagating as free-space beams”. That is, the Applicant’s claimed invention does not directly detect the signal powers from two optical fibers, and two beams from the free-space incur the cross-talk; and if the photodetectors are directly placed at the ends of two optical fibers (100-1 and 100-2) respectively, a cross-talk between the two photodetectors would not occur. In the system shown in Figure 2 of Liu ‘205, the two photo detectors (16/18. Or 11/13) are directly connected to two fibers (84/86), therefore, no crosstalk occurs.
Third, as to the phrase “stray light” used by Pacala, Pacala discloses “Stray light caused by roughness of optical surfaces, imperfections in transparent media, back reflections, etc., may be generated at various features within the receiver channel or external to receiver channel. When multiple receiver channels are arrayed adjacent to one another, this stray light in one receiver channel may be absorbed by a photosensor in another channel, thereby contaminating the timing, phase, or other information inherent to photons” ([0007] and [0163]); that is, the stray light can be generated by (or from neighboring receiver (photodetector assembly).
And Pacala further discloses “light propagating through bulk imaging optic can occasionally cause stray light to bleed into neighboring channels, thereby resulting in inaccurate readings of reflected light for each pixel in the field” ([0153]), “If multiple receiver channels are arrayed adjacent to one another, this stray light in one receiver channel may be absorbed by a photosensor in another channel, thereby contaminating the timing, phase, or other information inherent to photons. Accordingly, receiver channel 1700 may feature several structures to reduce crosstalk between receiver channels” ([0163]). That is, for a specific receiver A (photodetector), the leakage from another receiver B (photodetector) is a “stray light” with respect to receiver A; and for the receiver B, any leakage from receiver A is a “stray light” with respect to receiver B. Therefore, for the system shown in the figure on page 5 of current Office-Action, which is the combination of Liu'205, Liu'582, and Suzuki, the leakage from the photodetector 85-2 is a stray light for the photodetector 85-1; and in the same way, the leakage from the photodetector 85-1 is a stray light for the photodetector 85-2.
Pacala clearly discloses that the structure of the aperture and the housing is used to minimize/reduce crosstalk between the signals impinging receiver channels ([0049], [0163], and [0169]-[0170] etc.). “Optical lens layer 1750 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Optical filter layer 1760 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Photosensor layer 1770 refers to a layer made of photodetector(s) and contains optional structures to improve detection efficiency and reduce cross talk with neighboring receiver structures” ([0160]-[0162]), “aperture 2144 can absorb or reflect errant light rays passed by the light filter or reflected by the photosensor to further reduce crosstalk between receiver channels, thereby further increasing SNR (Signal to Noise Ratio) of the system” ([0197], [0202]), and “receiver channel 2232 includes sidewalls 2263 between optically non-transparent stop region 2246 and photosensor layer 2270 with photodetectors 2271 to reduce crosstalk. Sidewalls 2263 can be made up of optically non-transparent material or made up of optically transparent material” ([0219], [0223]-[0224], [0226] and [0233]). That is, the housing (with sidewalls) of the photodiode is used to reduce crosstalk between the photodiodes (receivers). The housing with aperture/sidewalls is not just for the beams transmitted from the free space or for “free-space light from a wide field-of-view”, instead, the housing with aperture/sidewalls is used to minimize crosstalk between the signals impinging the photodiodes. By using separated housing (with separated aperture and sidewalls), the photodiodes are optically-isolated; and crosstalk between the signals impinging two photodiodes are minimized.
Therefore, it is obvious to one skilled in the art to combine Pacala et al with Liu ‘205 and Liu ‘582 and Suzuki et al so to use a housing with aperture to minimize/reduce crosstalk between to the signals impinging a pair of photodetectors.
The combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests a system as shown in following figure.
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Therefore, one skilled in the art would “find it obvious to modify Liu'205, Liu'582, and Suzuki in a manner that arrives at the arrangement set forth in claims 1-3, 5, and 12”, and the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al reads on the claimed limitations.
It is worth pointing out that based on Applicant’s disclosure, applicant’s optically-isolated pair of photodiodes (12 and 14) are used to “minimizes the possibility of crosstalk between the signals impinging the pair of photodiodes” (Spec. [0017], “The use of separate housings and separate apertures form an optically-isolated arrangement that minimizes the possibility of crosstalk between the signals impinging the pair of photodiodes”), the housing itself does not separate the incoming beams, instead, the GRIN lens separate optical beams ([0005], “the propagating signals passing through the GRIN lens as individual and spatially separate optical signals”); and “As a result of using GRIN lens 32 in combination with the optically-isolated pair of photodiodes 12 and 14, bidirectional power monitor 10 is able to simultaneously measure the optical power in signals propagating in each direction along optical fiber 100” ([0020]); as shown in Applicant’s Figures 1-2 and 4, the light beam O1f directed to photodiode 12 will not enter the photodiode 14, and light beam O2f directed to photodiode 14 will not enter the photodiode 12. And without a housing, the “stray” or scattering light from one photodiode would enter another photodiode, so a crosstalk occurs; then, “The use of separate housings and separate apertures form an optically-isolated arrangement that minimizes the possibility of crosstalk between the signals impinging the pair of photodiodes”. That is, based on applicant’s Specification, the housing structure is used to minimize the crosstalk between the two photodiodes.
4). Applicant’s argument – In response to a similar position presented in the Applicant's prior response, the Final Office Action on page 9 submits that Pacala clearly disclose that the structure of the aperture and housing is used to minimize/reduce crosstalk between the signals impinging receiver channels. The Applicant appreciates that Pacala may disclose structures for minimizing/reducing crosstalk between receiver channels. The Applicant's point is that the structures for minimizing/reduce crosstalk between receiver channels are many-fold due to the nature of the received light. Namely, given Pacala is directed to an imaging system the light has a very wide field-of-view and a wide range of different angles. As such, the micro-optical receivers of Pacala are not positioned in relation to a lensing arrangement such that their respective housing apertures optically-isolate and reduce cross-talk between a first and second optical tap beam. Instead, Pacala discloses micro-optical receivers having structured features that reduce or minimize cross-talk after such light is spread across and received by multiple micro-optical receiver apertures.
Thus, Pacala alone or in combination Liu'205, Liu'582, and Suzuki does not disclose "wherein positioning of the first photodiode housing and the first photodiode housing aperture and positioning of the second photodiode housing and the second photodiode housing aperture in relation to the lensing arrangement ensures that a first free-space optical tap beam and a second free-space optical tap beam of the pair of free-space optical tap beams respectively passes through the first photodiode housing aperture and the second photodiode housing aperture and not respectively through the second photodiode housing aperture and the first photodiode housing aperture."
Examiner’s response – first, as discussed above, the Pacala’s housing with aperture/sidewalls is not just for the beams transmitted from the free space or for “light has a very wide field-of-view and a wide range of different angles”, instead, the housing with aperture/sidewalls is used to minimize crosstalk between the signals impinging the photodiodes. By using separated housing (with separated aperture and sidewalls), the photodiodes are optically-isolated; and crosstalk between the signals impinging two photodiodes are minimized. Therefore, applicant’s argument “Instead, Pacala discloses micro-optical receivers having structured features that reduce or minimize cross-talk after such light is spread across and received by multiple micro-optical receiver apertures” is incorrect.
The combination of Liu'205 and Liu'582 and Suzuki and Pacala teaches/suggests "wherein positioning of the first photodiode housing and the first photodiode housing aperture and positioning of the second photodiode housing and the second photodiode housing aperture in relation to the lensing arrangement ensures that a first free-space optical tap beam and a second free-space optical tap beam of the pair of free-space optical tap beams respectively passes through the first photodiode housing aperture and the second photodiode housing aperture and not respectively through the second photodiode housing aperture and the first photodiode housing aperture."
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-3, 5, 8-9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al (US 2020/0304205. Hereinafter Liu ‘205) in view of Liu et al (US 2018/0372582. Hereinafter Liu’582) and Suzuki et al (US 2007/0036491) and Pacala et al (US 2018/0329065).
1). With regard to claim 1, Liu ‘205 discloses an optical power monitor (e.g., Figures 2 and 3 etc.) for use with an optical fiber (fiber 82 and 80. [0001] “in-line bi-directional testing”, optical signals transmitted from “IN 1” to “IN 2” and from “In 2” to “IN 1”, the test apparatus 10 in “in-line”, or an optical fiber is cut into two pieces 80/82 so that the optical apparatus is “in-line” to monitor the powers) supporting bidirectional signal propagation (“in-line bidirectional” testing and “power monitor”, [0041]), the optical power monitor comprising:
a bidirectional assembly (10 in Figures 2-3) disposed at a defined cut location (e.g., Figure 2, the location where the “in-line” testing apparatus 10 located. Or at the location at label “100” in Figure 3) along the optical fiber, the cut location forming a first fiber section (the section of fiber 82) with a far-end termination (the end to be inserted into the first or bottom “bore/channel” of the “two parallel bores or channels 66”) at the cut location and a second fiber section (the section of fiber 80) with a near-end termination (the end to be inserted into the second or top “bore/channel” of the “two parallel bores or channels 66”) at the cut location, the bidirectional assembly including:
a lensing arrangement (e.g., 62) disposed to receive as separate, spaced-apart inputs (“two parallel bores or channels 66” as separate, spaced-apart inputs; two inputs 200 and 300) the far-end termination of the first fiber section (signal 300 via 82) and the near-end termination of the second fiber section (signal 200 via 80. Figures 2-3, the two dotted lines show the signals in the lensing arrangement 62); and
a partially reflective element (70, [0029], “In embodiments where the beam splitter 72 is not included, e.g., as illustrated in FIGS. 2 and 3, the optical filter 70 may both filter and split the received light signals 200 and 300.” “one hundred minus alpha percent (100-a) % of the light signals 200 and 300 within the passband, and the transmitted portions 204 and 304 may include a % of the light signals 200 and 300 within the passband. In various embodiments, the percentage a may include any of the percentages described above with respect to the beam splitter 72”) disposed along an output endface of the lensing arrangement (Figures 2-3), the partially reflective element configured to allow a minor portion (a %; or 5%, [0028]-[0029]) of optical signals propagating through the lensing arrangement to pass through and exit the bidirectional assembly as a pair of free-space optical tap beams (Figure 3, the free-space between the reflector 70 and photodetector 11; the pair of free-space optical tap beams come out from the lens and filter/reflector 62/70, dotted lines in Figures 2 and 3), the partially reflective element redirecting a remaining, major portion ((100-a) %; or 95%, [0028]-[0029]) of the propagating signals to pass through the lensing arrangement a second time and be coupled into a proper one of the first (signal 202 in first fiber section 82) and second (signal 302 in second fiber section 80) fiber sections for maintaining continuity of a signal path direction; and
a first photodiode (e.g., 13 in Figure 2, or one detector of the multi-element detector in Figure 3; [0037], “In some embodiments, the photo detector 11 may be a multi-element detector, such that signal components from IN 1 or IN 2 can be detected separately”. In Figure 2, a pair of photodiodes 11/13) provides, based on the first free-space optical tap beam (e.g., the tap team tapped from signal 300 from the IN 2), a measurement of optical power for signals exiting along the far-end termination (IN 2) of the first fiber section (82); and
a second photodiode (e.g., 11 in Figure 2, or one detector of the multi-element detector in Figure 3) provides, based on the second free-space optical tap beam (e.g., the tap team tapped from signal 200 from the IN 1), a measurement of the optical power for exiting along the near-end termination (IN 1) of the second fiber section (the second fiber section 80. “signal components from IN 1 or IN 2 can be detected separately”, [0037], “In this embodiment, the sampled and wavelength-filtered signal components from IN 1 and IN 2, e.g., the first and second transmitted portions 204 and 304, can be detected and converted into electric signals directly by the optical test apparatus 10. In some embodiments, the photo detector 11 may be a multi-element detector, such that signal components from IN 1 or IN 2 can be detected separately. In other embodiments, the photodetector 11 may have only a single element, such that the total spectral power in IN 1 and IN 2, i.e., P1l and P2l, is detected. If the wavelength components from IN 1 and IN 2 are different P1l and P2l can still be measured separately. In this embodiment, the optical filter 70 can be prisms, gratings, optical thin film coating, or any other suitable components”).
But, in Figure 3, Liu ‘205 does not expressly discloses that the first optical photodiode and the second photodiode are implemented in a first photodiode housing and a second photodiode housing respectively, and each housing has a housing aperture, wherein the first photodiode comprises a first active region in optical alignment with the first photodiode housing aperture; a second photodiode housing comprising a second photodiode housing aperture, and the second photodiode comprises a second active region in optical alignment with the second photodiode housing aperture; wherein positioning of the first photodiode housing and the first photodiode housing aperture and positioning of the second photodiode housing and the second photodiode housing aperture in relation to the lensing arrangement ensures that a first free-space optical tap beam and a second free-space optical tap beam of the pair of free-space optical tap beam respectively passes through the first photodiode housing aperture and the second photodiode housing aperture and not respectively through the second photodiode housing aperture and the first photodiode housing aperture so as to optically-isolate and reduce cross-talk between the first free-space optical tap beam and the second free-space optical tap beam.
However, first, as shown in Figure 2, Liu ‘205 uses two parallel bores or channels 96 and two separated photodiodes (11 and 13), as well as the pigtails 84 and 86; then the signal to the photodiode 11 is separated/isolated from the signal to the photodiode 13. That is, the two photodiodes 11 and 13 are optically-isolated photodiodes.
Figure 2 shows that two photodiodes 11/13 are not integrated into the test apparatus 10. However, Liu ‘205 states “Optical test apparatus 10 may further include various components to facilitate the transmission of light from the test apparatus 10 to a measuring equipment such as a power meter or a photodetector which may be connected to and/or integrated with the test apparatus 10. These light transmissions may be provided through the first collimator 60 and via the optical filter 70 as discussed herein.” ([0024])
Second, in Figure 3, Liu ‘205 shows “a photodetector 11 integrated into the test apparatus 10” ([0037]). And, Liu ‘205 teaches/suggests that multi-element detector can be used to separately detect the components from IN 1 and IN 2 ([0037]).
Third, Liu ‘582, from the same applicant as Liu ‘205, discloses a similar bi-directional test apparatus (Figures 1 and 3), as shown in Figure 3, after the lensing arrangement (62) and reflector 70, the signals forms two paths (204 and 208), these two paths are separated by a distance (e.g., D as labeled by examiner in following Figure O1, which is adapted from Figure 3 of Liu 582’).
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Figure O1 (adapted from Figure 3 of Liu ‘582)
Another prior art, Suzuki et al, discloses a similar system to monitor the power/intensity of a signal transmitted in a fiber (Figure 7), as shown in Figure 7, optical signals are transmitted bidirectionally (solid-line from fiber 81 segment 81 to fiber segment 82, and dotted-line from fiber segment 82 to fiber segment 81); a partially reflective element 84 allow a minor portion of optical signals propagating through the lensing arrangement 83 to pass through and exit the bidirectional assembly as a pair of free-space optical tap beams (solid-line and broken-line from the mirror/tap film 84), the partially reflective element redirecting a remaining, major portion of the propagating signals to pass through the lensing arrangement a second time and be coupled into a proper one of the first and second fiber sections for maintaining continuity of a signal path direction (Figure 7, [0009]-[0010] and [0012]).
In Figure 7 of Suzuki et al, only one photo-detector (85) is used, and “The center line of the GRIN lens is disposed, shifted from that of the photo-detector 85 (equivalent to a photodiode)”, and then one of pair of free-space optical tap beams is sent to the photo-detector 85; and, the power of the incoming light from the input optical fiber 82 (port 2) is not measured ([0010], “The light, which has transmitted through the dielectric mirror, does not enter the photo-detector 85 but is discharged to the outside because the optical axis (center line) of GRIN lens is shifted from the optical axis (center line) of the photo-detector 85. Accordingly, the intensity of the incoming light from the output optical fiber 82 (port 2) is impossible to measure. Such a series of optical paths are indicated by broken-line arrows. In other words, there is used an optical power monitor which has uni-directionality, that is, the following phenomenon: the intensity of the incoming light from the input optical fiber 81 (port 1) is possible to measure and the intensity of the incoming light from the output optical fiber 82 (port 2) is not possible to measure”). However, since Liu ‘205 and Liu ‘258 discloses that two photodetectors can be used to measure the bidirectional optical powers and Liu ‘205 indicates that multi-element detector can be used to detect the components from IN 1 and IN 2 separately (for Figure 3). Also, for the embodiment shown in Figure 6, Suzuki et al discloses “an example of a bi-directional optical power monitor miniaturized for easy handling. FIG. 6 is a structure of the disclosed monitor. A multi-capillary glass ferrule 53 (equivalent to a pig tail fiber) having two optical fibers 51, 52, respectively (an input optical fiber 51 and an output optical fiber 52, respectively) and GRIN (Gradient Index) lens 54 are made to face each other through an air gap 55 with a predetermined length. On an end surface of the GRIN lens, a filter 56 (equivalent to a tap film) is provided to permit the light passing through the GRIN lens to reflect and penetrate. The light transmitting through the filter passes through an air gap 57 and is converted into an electric signal by a photon detector 58 (corresponding to a photodiode) to measure the intensity of the light inputted into the optical fiber. The multi-capillary glass ferrule 53 and the GRIN lens 54 are retained with glass tubes 60, 61. Because both the two optical fibers 51, 52 permits light inputs and outputs, this apparatus may be called a bi-directional optical power monitor.” That is, as long as the two light beams (solid-line and broken-line) can impinge on photodetector(s), a bi-directional power monitor can be realized. Then, it is obvious to one skilled in the art that another photodetector can be installed in the system of Figure 7 of Suzuki et al so that the system disclosed by Suzuki et al can be used for bi-directional power monitoring.
Following Figure O2 is the combination of Liu ‘205 and Liu ‘258 and Suzuki et al.
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Figure O2 (modified from Figure 7 of Suzuki)
And Suzuki et al also mentioned “If the GRIN lens approaches the photodiode too much, even the light transmitted from any optical fiber is detected, therefore the GRIN lens should be distant from the photodiode by at least a certain distance”; that is, as long as the distance between the GRIN lens and the photodiode is larger than a “certain distance” the light beam to one photodetector will not interfere with the light beam to another photodetector.
Liu ‘205 and Liu ‘582 and Suzuki et al do not expressly show a first photodiode housing and second photodiode housing.
However, first, as shown in Figure 2 of Liu ‘205, Figure 3 of Liu 582 and Figure 7 of Suzuki, due to the lensing arrangement and incident angle to the reflector, the two light beams passing through the reflector are separated. Second, since the two photodiodes are in a relatively compact space (e.g., in a protective sleeve), it is obvious to one skilled in the art to separate or isolate the two photodiodes so to reduce interference or crosstalk between the two photodiodes. E.g., Pacala et al discloses an optical signal detection scheme (Figure 2, 10 and 15 etc.) in which a plurality of photodetectors (micro-optic receiver channels) are used to detect optical signals transmitted in free-space, and a housing structure (e.g., Figure 17 etc.) is used for each of the micro-optic receiver channels (212 and 1012 in Figures 2 and 10), or each photodiode is implemented into individual housing ([0158], “Receiver channel 1700 can be representative of micro-optic receiver channels 232 and 1032, among others, shown in FIGS. 2 and 10, respectively, and serves to accept an input cone of light containing a wide range of wavelengths, filters out all but a narrow band of those wavelengths centered at the operating wavelength, and allows photosensor 1771 to detect only or substantially only photons within the aforementioned narrow band of wavelengths.” Note: in para [0158], there are typos, the “232 and 1032” should be “212 and 1012”), so to “reducing or eliminating any detrimental effects caused by the occurrence of stray light” ([0158] and [0163]-[0164]); by using the structure of receiver channel 1700, crosstalk between receiver channels are reduced/eliminated ([0008] and [0163] etc., “eliminating any detrimental effects caused by the occurrence of stray light”). That is, Pacala et al discloses to use multiple optically-isolated photodiodes to detect a plurality of optical signals transmitted in free-space, and the structure of the aperture and the housing is used to minimize/reduce crosstalk between the signals impinging receiver channels ([0049], [0163], and [0169]-[0170] etc.); and “Optical lens layer 1750 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Optical filter layer 1760 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Photosensor layer 1770 refers to a layer made of photodetector(s) and contains optional structures to improve detection efficiency and reduce cross talk with neighboring receiver structures” ([0160]-[0162]), “aperture 2144 can absorb or reflect errant light rays passed by the light filter or reflected by the photosensor to further reduce crosstalk between receiver channels, thereby further increasing SNR (Signal to Noise Ratio) of the system” ([0197], [0202]), and “receiver channel 2232 includes sidewalls 2263 between optically non-transparent stop region 2246 and photosensor layer 2270 with photodetectors 2271 to reduce crosstalk. Sidewalls 2263 can be made up of optically non-transparent material or made up of optically transparent material” ([0219], [0223]-[0224], [0226] and [0233]). That is, the housing (with sidewalls) of the photodiode is used to reduce crosstalk between the photodiodes (receivers). By using separated housing (with separated aperture and sidewalls), the photodiodes are optically-isolated; and crosstalk between the signals impinging two photodiodes is minimized.
Then, by combining Pacala et al with Liu ‘205 and Liu ‘582 and Suzuki et al, an bidirectional optical power monitor with optically-isolated photodiodes can be obtained, following Figure O3 shows an bidirectional optical power monitor based on the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al.
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Figure O3
As shown in Figure O3 above, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al discloses a bidirectional power monitor, which comprising:
a first photodiode housing (the “first photodiode housing” shown in Figure O3) comprising a first photodiode housing aperture (the “first photodiode housing aperture” shown in Figure O3);
a first photodiode (in the “first active region”, Pacala: [0158]) in the first photodiode housing, wherein the first photodiode comprises a first active region (the “first active region” in Figure O3; or Pacala: 1771 in Figure 17) in optical alignment with the first photodiode housing aperture (Figure O3, and Pacala: [0158]-[0166]);
a second photodiode housing (the “second photodiode housing” shown in Figure O3) comprising a second photodiode housing aperture (the “second photodiode housing aperture” shown in Figure O3); and
a second photodiode (in the “second active region”, Pacala: [0158]) in the second photodiode housing, wherein the second photodiode comprises a second active region (the “second active region”; or Pacala: 1771 in Figure 17) in optical alignment with the second photodiode housing aperture (Figure O3, and Pacala: [0158]-[0166]);
wherein positioning of the first photodiode housing and the first photodiode housing aperture and positioning of the second photodiode housing and the second photodiode housing aperture in relation to the lensing arrangement (83 in Figure O3. Suzuki: [0009]-[0010] and [0012]; and Liu ‘582: [0045]-[0047], lens 62 in Figure 3 separates the two beams 204/208) ensures that a first free-space optical tap beam (the broken-line arrows between the dielectric mirror 84 and the first photodiode housing aperture) and a second free-space optical tap beam (the solid-line arrows between the dielectric mirror 84 and the second photodiode housing aperture) of the pair of free-space optical tap beam (the two tap beams from the dielectric mirror 84) respectively passes through the first photodiode housing aperture and the second photodiode housing aperture (Figure O3. Suzuki: [0009]-[0010] and [0012]) and not respectively through the second photodiode housing aperture and the first photodiode housing aperture (due to the GRIN lens and the distance between the GRIN lens and the photodiode housings; Suzuki: [0009]-[0010] and [0012]) so as to optically-isolate and reduce cross-talk (Figure O3, and Pacala: [0049], [0163], [0169]-[0170], [0197], [0202], [0219], [0223]-[0224], [0226] and [0233] etc.) between the first free-space optical tap beam and the second free-space optical tap beam (Pacala: [0049], [0163], [0169]-[0170], [0197], [0202], [0219], [0223]-[0224], [0226] and [0233] etc.).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Liu ‘582 and Suzuki et al and Pacala et al to the system/method of Liu ‘205 so that a pair of optically-isolated photodiodes are installed in the photodetector section with each photodiode having its own housing/aperture to prevent crosstalk (or “stray light”), and the system is compact and integrated.
2). With regard to claim 2, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al further discloses wherein the minor portion of the optical signals passing through the partially reflective element is in a range of about 1%-10% of the optical power, and the major portion redirected through the lensing arrangement a second time in the range of about 99%-90%, in conjunction with the minor portion range (Liu ‘205: [0028]-[0029]).
3). With regard to claim 3, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al further discloses wherein the lensing arrangement comprises a graded index (GRIN) lens (Liu ‘205: [0020] and [0030] etc. “The lens may, in some embodiments, be a graded-index lens”. Liu ‘582: [0027] and [0035] etc. “The lens may, in some embodiments, be a graded-index lens”. Suzuki: GRIN lens 83).
4). With regard to claim 5, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al further discloses where the bidirectional assembly further comprises:
a dual-core capillary (Liu ‘205: two parallel bores or channels 66. Liu ‘582: Figure 3. Suzuki: two-core ferrule 80) disposed at an input endface (Liu ‘205: the endface between the ferrule 64 and the lens 62. Liu ‘582: the endface between the ferrule 64 and the lens 62. Suzuki: the endface between the two-core ferrule 80 and the GRIN lens 83. The input endface is relative to the lens, or “to the lensing arrangement”, or it is an input endface of lens (62 of Liu, 83 of Suzuki) to the lensing arrangement;
wherein the dual-core capillary comprises a pair of hollow cores (Liu ‘205: “two parallel bores or channels 66”, [0020]. Liu ‘582: “two parallel channels 66 extending therethrough. Each channel 66 may accommodate an optical fiber therein for connection to the collimator 60”, [0027]. Suzuki: “the two-core ferrule”, [0009]);
wherein each hollow core supports a separate one of the first and second fiber sections (Liu: 80/82. Suzuki: 81/82);
wherein the first and second fiber sections extends through the hollow cores along a longitudinal extent of the dual-core capillary (Liu ‘205 and Liu ‘582: Figures 1-3, respectively. Suzuki: Figure 7); and
wherein an output endface (Liu ‘205: the endface between the ferrule 64 and the lens 62. Liu ‘582: the endface between the ferrule 64 and the lens 62. Suzuki: the endface between the two-core ferrule 80 and the GRIN lens 83. The output endface is relative to the ferrule 64 or two0cre ferrule 80, or the output endface is the endface of the dual-core capillary/ferrule) of the dual-core capillary is disposed adjacent to the lensing arrangement (Liu: lens 62; Suzuki: lens 83. And Liu: at the contact point between ferrule 64 and the lensing arrangement 62. Suzuki: Figure 7), providing optical coupling of the far-end termination of the first fiber section and the near-end termination of the second fiber section to the lensing arrangement in a spatially separated position determined by a spacing between the hollow cores (Liu ‘205: Figures 2-3, and Liu ‘582: Figures 1 and 3. Suzuki: Figure 7, [0009]-[0010] and [0012]).
5). With regard to claim 8, Liu ‘205 discloses a method of performing simultaneous power measurements of optical signals propagating in opposing directions along a bidirectional optical fiber (Figures 2-3 etc.; fiber 82 and 80. [0001] “in-line bi-directional testing”, optical signals transmitted from “IN 1” to “IN 2” and from “In 2” to “IN 1”, the test apparatus 10 in “in-line”, or an optical fiber is cut into two pieces 80/82 so that the optical apparatus is “in-line” to monitor the powers), the method comprising the steps of:
inserting an optical power monitor (e.g., 10 in Figures 2 and 3 etc.) at a defined cut location (e.g., Figure 2, the location where the “in-line” testing apparatus 10 located. Or at the location at label “100” in Figure 3) along the bidirectional optical fiber, the cut location forming a first fiber section (the section of fiber 82) with a far-end termination (the end to be inserted into the first or bottom “bore/channel” of the “two parallel bores or channels 66”) at the cut location and a second fiber section (the section of fiber 80) with a near-end termination (the end to be inserted into the second or top “bore/channel” of the “two parallel bores or channels 66”) at the cut location, the optical power monitoring including a lensing arrangement (e.g., 62), a partially reflective element (70, [0029], “In embodiments where the beam splitter 72 is not included, e.g., as illustrated in FIGS. 2 and 3, the optical filter 70 may both filter and split the received light signals 200 and 300.” “one hundred minus alpha percent (100-a) % of the light signals 200 and 300 within the passband, and the transmitted portions 204 and 304 may include a % of the light signals 200 and 300 within the passband. In various embodiments, the percentage a may include any of the percentages described above with respect to the beam splitter 72”) disposed along an output endface of the lensing arrangement (Figures 2-3), and a pair of photodiodes ([0037], “In some embodiments, the photo detector 11 may be a multi-element detector, such that signal components from IN 1 or IN 2 can be detected separately”. In Figure 2, a pair of photodiodes 11/13) disposed in optical alignment with the partially reflective element (Figure 3, [0037]);
coupling the far-end termination of the first fiber section to an input endface (at the contact face between ferrule 64 and the lensing arrangement 62) of the lensing arrangement at a first location (Figure 2-3, at the location of one of the “two parallel bores or channels 66” contacts the lensing 62, e.g., at the bottom bore/channel);
coupling the near-end termination of the second fiber section to the input endface of the lensing arrangement at a second location (Figure 2-3, at the location of another one of the “two parallel bores or channels 66” contacts the lensing 62, e.g., at the top bore/channel) spaced apart from the first location (Figures 2-3, two parallel and separate bores or channels 66);
receiving, at a first photodiode of the pair of photodiodes (e.g., photodiode 13 in Figure 2; or one detector in the multi-element detector in Figure 3), a first free-space optical tap beam (e.g., the tap team tapped from signal 300 from the IN 2) from the partially reflective element (70), where the first free-space optical tap beam is a minor portion (a %; or 5%, [0028]-[0029]) of a first optical signal (from IN2) entering from the far-end termination of the first fiber section (fiber section 82. [0029], “In embodiments where the beam splitter 72 is not included, e.g., as illustrated in FIGS. 2 and 3, the optical filter 70 may both filter and split the received light signals 200 and 300.” “one hundred minus alpha percent (100-a) % of the light signals 200 and 300 within the passband, and the transmitted portions 204 and 304 may include a % of the light signals 200 and 300 within the passband. In various embodiments, the percentage a may include any of the percentages described above with respect to the beam splitter 72”);
directing a major portion ((100-a) %; or 95%, [0028]-[0029]) of the optical signal from the partially reflective element into the near-end termination of the second fiber section (Figures 2-3);
receiving, at a second photodiode (e.g., 11 in Figure 2, or one detector of the multi-element detector in Figure 3) of the pair of optically-isolated photodiodes, a second free-space optical tap beam (e.g., the tap team tapped from signal 200 from the IN 1) from the partially reflective element (70), where the second free-space optical tap beam is a minor portion (a %; or 5%, [0028]-[0029]) of a second optical signal (from IN1) entering the near-end termination of the second fiber section (fiber section 80. [0029], “In embodiments where the beam splitter 72 is not included, e.g., as illustrated in FIGS. 2 and 3, the optical filter 70 may both filter and split the received light signals 200 and 300.” “one hundred minus alpha percent (100-a) % of the light signals 200 and 300 within the passband, and the transmitted portions 204 and 304 may include a % of the light signals 200 and 300 within the passband. In various embodiments, the percentage a may include any of the percentages described above with respect to the beam splitter 72”);
directing a major portion ((100-a) %; or 95%, [0028]-[0029]) of the second optical signal from the partially reflective element into the far-end termination of the first fiber section (Figures 2-3);
converting the first free-space optical tap beam received by the first photodiode into a first electrical representation of optical power for the major portion of the first optical signal (Figures 2-3, and [0037]-[0041]; 300 -> 304 detected by P2; the purpose of the optical power monitor); and
converting the second free-space optical tap beam received by the second photodiode into a second electrical representation of optical power for the major portion of the second optical signal (Figures 2-3, and [0037]-[0041]; 200 -> 204 detected by P1; the purpose of the optical power monitor).
But, in Figure 3, Liu ‘205 does not expressly show the pair of optically-isolated photodiodes disposed in alignment with the partially reflective element; and Liu ‘205 does not expressly disclose: the first optical photodiode receives the first free-space optical tap beam via a first photodiode housing aperture of a first photodiode housing, and the second photodiode receives the second free-space optical tap beam via a second photodiode housing aperture of a second photodiode housing, and wherein the first photodiode housing, the first photodiode housing aperture, the second photodiode housing, and the second photodiode housing aperture in conjunction with the lensing arrangement ensures that the first free-space optical tap beam and the second free-space optical tap beam respectively passes through the first photodiode housing aperture and the second photodiode housing aperture and not respectively through the second photodiode housing aperture and the first photodiode housing aperture so as to optically-isolate and reduce cross-talk between the first free-space optical tap beam and the second free-space optical tap beam.
However, first, as shown in Figure 2, Liu ‘205 uses two parallel bores or channels 96 and two separated photodiodes (11 and 13), as well as the pigtails 84 and 86; then the signal to the photodiode 11 is separated/isolated from the signal to the photodiode 13. That is, the two photodiodes 11 and 13 are optically-isolated photodiodes.
Figure 2 shows that two photodiodes 11/13 are not integrated into the test apparatus 10. However, Liu ‘205 states “Optical test apparatus 10 may further include various components to facilitate the transmission of light from the test apparatus 10 to a measuring equipment such as a power meter or a photodetector which may be connected to and/or integrated with the test apparatus 10. These light transmissions may be provided through the first collimator 60 and via the optical filter 70 as discussed herein.” ([0024])
Second, in Figure 3, Liu ‘205 shows “a photodetector 11 integrated into the test apparatus 10” ([0037]). And, Liu ‘205 teaches/suggests that multi-element detector can be used to separately detect the components from IN 1 and IN 2 ([0037]).
Third, Liu ‘582, from the same applicant, discloses a similar bi-directional test apparatus (Figures 1 and 3), as shown in Figure 3, after the lensing arrangement (62) and reflector 70, the signals forms two paths (204 and 208), these two paths are separated by a distance (e.g., D as labeled by examiner in Figure O1 above).
Another prior art, Suzuki et al, discloses a similar system to monitor the power/intensity of a signal transmitted in a fiber (Figure 7), as shown in Figure 7, optical signals are transmitted bidirectionally (solid-line from fiber 81 segment 81 to fiber segment 82, and dotted-line from fiber segment 82 to fiber segment 81); a partially reflective element 84 allow a minor portion of optical signals propagating through the lensing arrangement 83 to pass through and exit the bidirectional assembly as a pair of free-space optical tap beams (solid-line and broken-line from the mirror/tap film 84), the partially reflective element redirecting a remaining, major portion of the propagating signals to pass through the lensing arrangement a second time and be coupled into a proper one of the first and second fiber sections for maintaining continuity of a signal path direction (Figure 7, [0009]-[0010] and [0012]).
In Figure 7 of Suzuki et al, only one photo-detector (85) is used, and “The center line of the GRIN lens is disposed, shifted from that of the photo-detector 85 (equivalent to a photodiode)”, and then one of pair of free-space optical tap beams is sent to the photo-detector 85; and, the power of the incoming light from the input optical fiber 82 (port 2) is not measured ([0010], “The light, which has transmitted through the dielectric mirror, does not enter the photo-detector 85 but is discharged to the outside because the optical axis (center line) of GRIN lens is shifted from the optical axis (center line) of the photo-detector 85. Accordingly, the intensity of the incoming light from the output optical fiber 82 (port 2) is impossible to measure. Such a series of optical paths are indicated by broken-line arrows. In other words, there is used an optical power monitor which has uni-directionality, that is, the following phenomenon: the intensity of the incoming light from the input optical fiber 81 (port 1) is possible to measure and the intensity of the incoming light from the output optical fiber 82 (port 2) is not possible to measure”). However, since Liu ‘205 and Liu ‘258 discloses that two photodetectors can be used to measure the bidirectional optical powers and Liu ‘205 indicates that multi-element detector can be used to detect the components from IN 1 and IN 2 separately (for Figure 3). Also, for the embodiment shown in Figure 6, Suzuki et al discloses “an example of a bi-directional optical power monitor miniaturized for easy handling. FIG. 6 is a structure of the disclosed monitor. A multi-capillary glass ferrule 53 (equivalent to a pig tail fiber) having two optical fibers 51, 52, respectively (an input optical fiber 51 and an output optical fiber 52, respectively) and GRIN (Gradient Index) lens 54 are made to face each other through an air gap 55 with a predetermined length. On an end surface of the GRIN lens, a filter 56 (equivalent to a tap film) is provided to permit the light passing through the GRIN lens to reflect and penetrate. The light transmitting through the filter passes through an air gap 57 and is converted into an electric signal by a photon detector 58 (corresponding to a photodiode) to measure the intensity of the light inputted into the optical fiber. The multi-capillary glass ferrule 53 and the GRIN lens 54 are retained with glass tubes 60, 61. Because both the two optical fibers 51, 52 permits light inputs and outputs, this apparatus may be called a bi-directional optical power monitor.” That is, as long as the two light beams (solid-line and broken-line) can impinge on photodetector(s), a bi-directional power monitor can be realized. Then, it is obvious to one skilled in the art that another photodetector can be installed in the system of Figure 7 of Suzuki et al so that the system disclosed by Suzuki et al can be used for bi-directional power monitoring. Figure O2 above is the combination of Liu ‘205 and Liu ‘258 and Suzuki et al.
And Suzuki et al also mentioned “If the GRIN lens approaches the photodiode too much, even the light transmitted from any optical fiber is detected, therefore the GRIN lens should be distant from the photodiode by at least a certain distance”; that is, as long as the distance between the GRIN lens and the photodiode is larger than a “certain distance” the light beam to one photodetector will not interfere with the light beam to another photodetector.
Liu ‘205 and Liu ‘582 and Suzuki et al does not expressly show the “optically-isolated” structure of the photodetector.
However, first, as shown in Figure 2 of Liu ‘205, Figure 3 of Liu 582 and Figure 7 of Suzuki, due to the lensing arrangement and incident angle to the reflector, the two light beams passing through the reflector are separated. Second, since the two photodiodes are in a relatively compact space (e.g., in a protective sleeve), it is obvious to one skilled in the art to separate or isolate the two photodiodes so to reduce interference or crosstalk between the two photodiodes. E.g., Pacala et al discloses an optical signal detection scheme (Figure 2, 10 and 15 etc.) in which a plurality of photodetectors (micro-optic receiver channels) are used to detect optical signals transmitted in free-space, and a housing structure (e.g., Figure 17 etc.) is used for each of the micro-optic receiver channels (212 and 1012 in Figures 2 and 10), or each photodiode is implemented into individual housing ([0158], “Receiver channel 1700 can be representative of micro-optic receiver channels 232 and 1032, among others, shown in FIGS. 2 and 10, respectively, and serves to accept an input cone of light containing a wide range of wavelengths, filters out all but a narrow band of those wavelengths centered at the operating wavelength, and allows photosensor 1771 to detect only or substantially only photons within the aforementioned narrow band of wavelengths.” Note: in para [0158], there are typos, the “232 and 1032” should be “212 and 1012”), so to “reducing or eliminating any detrimental effects caused by the occurrence of stray light” ([0158] and [0163]-[0164]); by using the structure of receiver channel 1700, crosstalk between receiver channels are reduced/eliminated ([0008] and [0163] etc., “eliminating any detrimental effects caused by the occurrence of stray light”). That is, Pacala et al discloses to use multiple optically-isolated photodiodes to detect a plurality of optical signals transmitted in free-space, and the structure of the aperture and the housing is used to minimize/reduce crosstalk between the signals impinging receiver channels ([0049], [0163], and [0169]-[0170] etc.); and “Optical lens layer 1750 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Optical filter layer 1760 may optionally include apertures, optically non-transparent regions and tube structures to reduce cross talk. … Photosensor layer 1770 refers to a layer made of photodetector(s) and contains optional structures to improve detection efficiency and reduce cross talk with neighboring receiver structures” ([0160]-[0162]), “aperture 2144 can absorb or reflect errant light rays passed by the light filter or reflected by the photosensor to further reduce crosstalk between receiver channels, thereby further increasing SNR (Signal to Noise Ratio) of the system” ([0197], [0202]), and “receiver channel 2232 includes sidewalls 2263 between optically non-transparent stop region 2246 and photosensor layer 2270 with photodetectors 2271 to reduce crosstalk. Sidewalls 2263 can be made up of optically non-transparent material or made up of optically transparent material” ([0219], [0223]-[0224], [0226] and [0233]). That is, the housing (with sidewalls) of the photodiode is used to reduce crosstalk between the photodiodes (receivers). By using separated housing (with separated aperture and sidewalls), the photodiodes are optically-isolated; and crosstalk between the signals impinging two photodiodes is minimized.
Then, by combining Pacala et al with Liu ‘205 and Liu ‘582 and Suzuki et al, an bidirectional optical power monitor with optically-isolated photodiodes can be obtained, Figure O3 above (page 26) shows an bidirectional optical power monitor based on the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al.
As shown in Figure O3 above (page 26), the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al discloses a bidirectional power monitor method, which comprising steps:
receiving, at a first photodiode (in the “first active region” of Figure O3, Pacala: [0158]) of the pair of optically-isolated photodiodes (in the first and second photodiodes housings, Figure O3) via a first photodiode housing aperture (the “first photodiode housing aperture” shown in Figure O3) of a first photodiode housing (the “first photodiode housing”), a first free-space optical tap beam (the broken-line arrows between the dielectric mirror 84 and the first photodiode housing aperture) from the partially reflective element (the dielectric mirror 84);
receiving, at a second photodiode (in the “second active region” of Figure O3, Pacala: [0158]) of the pair of optically-isolated photodiodes via a second photodiode housing aperture (the “second photodiode housing aperture” shown in Figure O3) of a second photodiode housing (the “second photodiode housing”), a second free- space optical tap beam (the solid-line arrows between the dielectric mirror 84 and the second photodiode housing aperture) from the partially reflective element;
wherein the first photodiode housing, the first photodiode housing aperture, the second photodiode housing, and the second photodiode housing aperture in conjunction with the lensing arrangement (83 in Figure O3. Suzuki: [0009]-[0010] and [0012]; and Liu ‘582: [0045]-[0047], lens 62 in Figure 3 separates the two beams 204/208) ensures that the first free-space optical tap beam and the second free-space optical tap beam respectively passes through the first photodiode housing aperture and the second photodiode housing aperture (due to the GRIN lens and the distance between the GRIN lens and the photodiode housings; Suzuki: [0009]-[0010] and [0012]) and not respectively through the second photodiode housing aperture and the first photodiode housing aperture (due to the GRIN lens and the proper distance between the GRIN lens and the photodiode housings; Suzuki: [0009]-[0010] and [0012]) so as optically-isolate and reduce cross-talk (Figure O3, and Pacala: [0049], [0163], [0169]-[0170], [0197], [0202], [0219], [0223]-[0224], [0226] and [0233] etc.) between the first free-space optical tap beam and the second free-space optical tap beam (Pacala: [0049], [0163], [0169]-[0170], [0197], [0202], [0219], [0223]-[0224], [0226] and [0233] etc.).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Liu ‘582 and Suzuki et al and Pacala et al to the system/method of Liu ‘205 so that a pair of optically-isolated photodiodes are installed in the photodetector section with each photodiode having its own housing/aperture to prevent crosstalk (or “stray light”), and the system is compact and integrated.
6). With regard to claim 9, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 8 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al further discloses the method as defined in claim 8 comprising:
determining the optical power for the major portion of the first optical signal by multiplying the first electrical representation by a factor related to a defined reflectance percentage of the partially reflective element (Liu ‘205: [0028]-[0029]; and [0040], “The transmitted light 204 and 304 may be converted by the photodetector(s) 11 and/or 13 to an electrical signal, and the electrical signal may be transmitted from the photodetector(s) 11 and/or 13 to a power monitor or a power meter”; since it is a power meter to measure the optical power and a specific percentage of the power is monitored and converted into electrical signal, it is obvious to one skilled in the art that a specific factor or “multiplying” or calibration is needed/used to obtain the actual optical power from the measured electrical representation. It is also common practice in conventional optical power monitor that by knowing a specific optical power percentage associated with the tap fiber or the partially reflective element, the measurement by the photodiode (electrical representation) can be multiplied by a proper factor to find the actual power of the signal propagating along the main signal path. E.g., when a 5% of light from an input passes through the reflective element, and the optical power of the tapped (or passed) beam is measured as 0.05 watts, then the major portion (reflected) of the optical signal is 0.95 watts); and
determining the optical power for the major portion of the second optical signal by multiplying the second electrical representation by the factor related to the defined reflectance percentage of the partially reflective element (Liu ‘205: [0028]-[0029]; and [0040], “The transmitted light 204 and 304 may be converted by the photodetector(s) 11 and/or 13 to an electrical signal, and the electrical signal may be transmitted from the photodetector(s) 11 and/or 13 to a power monitor or a power meter”; since it is a power meter to measure the optical power and a specific percentage of the power is monitored and converted into electrical signal, it is obvious to one skilled in the art that a specific factor or “multiplying” or calibration is needed/used to obtain the actual optical power from the measured electrical representation. It is also common practice in conventional optical power monitor that by knowing a specific optical power percentage associated with the tap fiber or the partially reflective element, the measurement by the photodiode (electrical representation) can be multiplied by a proper factor to find the actual power of the signal propagating along the main signal path. E.g., when a 5% of light from an input passes through the reflective element, and the optical power of the tapped (or passed) beam is measured as 0.05 watts, then the major portion (reflected) of the optical signal is 0.95 watts).
7). With regard to claim 12, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 8 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al further discloses wherein the far-end termination of the first fiber section and the near-end termination of the second fiber section direct optical signals into an input endface of the GRIN lens (Liu ‘205: Figures 2-3, the input endface of the lens 62, which accepts the light inputs from the two fibers accommodated in the two parallel bores/channels 66. Liu ‘582: Figure 3, the input endface of the lens 62, which accepts the light inputs from the two fibers accommodated in the two parallel bores/channels 66. Suzuki: Figure 7, the input endface of the GRIN lens 83, which accepts the light inputs from the two fibers 81/83 accommodated in the two two-core ferrule 80).
Claims 6-7, 10 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al as applied to claim 1 above, and further in view of Kobayashi et al (Kobayashi et al: “Performance of a Reflective Erbium-Doped Fiber Amplifier Pumped by a 1480-nm Laser Diode”, 1993 OSA Technical Digest Series (Optica Publishing Group, 1993), paper MA2, pages 88-91).
1). With regard to claim 6, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose wherein: a near-end termination of the first fiber section is coupled to a bidirectional port of an optical circulator; and a far-end termination of the second fiber section is coupled to a reflective element for redirecting a propagating signal to propagate in a reverse direction along the second fiber section and pass a second time through the optical power monitor prior to being coupled into the directional port of the optical circulator, the optical power monitor providing a measure of optical input power at the first photodiode and a measure of optical output power at the second photodiode.
However, first, Liu ‘205 discloses that one optical test apparatus can connected to other optical test apparatuses (Figures 5-6), and Liu ‘582 discloses “The test apparatus 10 may, for example, include a light source 20. The light source 20 may generate light (i.e. infrared light) at one or more suitable predetermined wavelengths for transmission through the other components of the test apparatus 10. … The test apparatus 10 may further include an optical connector 30. A test jumper 32 may extend from the optical connector 30. An optical fiber 34 to be tested (i.e. a fiber under test) may be connected to the optical connector 30, i.e. via the jumper 32.”, that is the light source sends optical signals to the fiber under test (34), the reflected or reversed signals from the fiber-under-test 34 is detected by the photodiode 40 in the test apparatus 10; also refer to Figure O3 above. Therefore, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests: a far-end termination of the second fiber section (“fiber under test”) is coupled to a reflective element (e.g., reflective portion/element in the “fiber under test”) for redirecting a propagating signal (from the light source 20) to propagate in a reverse direction along the second fiber section (back to the test apparatus) and pass a second time through the optical power monitor, the optical power monitor providing a measure of optical input power at the first photodiode (e.g., 50 of Liu ‘582) and a measure of optical output power at the second photodiode (e.g., 40 of Liu ‘582).
Also, another prior art, Kobayashi et al, discloses a reflective Erbium Doped Fiber Amplifier (EDFA) (Figure 1), and Kobayashi et al discloses that the performance of the reflective EDFA is measured and calculated (page 88, Introduction), and gain efficiency is measured/obtained (Figure 2(2) and Figure 4-6). To measure the gain etc., the input optical power and output optical power need to be measured. Since the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests a bi-directional optical power monitor, which can be used to measure sending (transmission) power and reflected (or reversed) signal power, it is obvious to one skilled in the art to use the bi-directional optical power monitor to measure the gain of the reflective EDFA.
As shown in Figure 1, Kobayashi et al discloses a near-end termination of a first fiber section (the fiber for “SIGNAL INPUT”) is coupled to a bidirectional port of an optical circulator (“OPTICAL CIRCULATOR”); and a far-end termination of the second fiber section is coupled to a reflective element (“REFLECTOR” in Figure 1) for redirecting a propagating signal to propagate in a reverse direction along the second fiber section.
By combing Kobayashi et al with Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al, a system/method for measuring the performance of a reflective EDFA is obtained as following Figure O4.
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Figure O4
As shown in Figure O4 above, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al teaches/suggests: a near-end termination (to the power monitor) of the first fiber section (from “OPTICAL CIRCULATOR” to the power monitor) is coupled to a bidirectional port (one of the three ports of the Optical Circulator; the port at the right side to the power monitor or Reflector) of an optical circulator (the “OPTICAL CIRCULATOR”); and
a far-end termination (at the “REFLECTOR”) of the second fiber section (from the power monitor to the REFLECTOR) is coupled to a reflective element (“REFLECTOR”) for redirecting a propagating signal (reflected by the REFLECTOR) to propagate in a reverse direction along the second fiber section and pass a second time through the optical power monitor prior to being coupled into the directional port of the optical circulator (Figure O4), the optical power monitor providing a measure of optical input power at the first photodiode and a measure of optical output power at the second photodiode (refer claim 1 rejection above).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine Kobayashi et al with Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al so that the bidirectional power monitor can be used to measure the gain of a reflective EDFA quickly and conveniently.
2). With regard to claim 7, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al disclose all of the subject matter as applied to claims 1 and 6 above. And the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al further discloses wherein at least a portion of the second fiber section comprises a length of rare-earth doped optical fiber (Kobayashi: EDF) also responsive to an optical pump beam (Kobayashi: from PUMP LD (1480 nm)) so as to form an optical amplifier (Kobayashi: reflective EDF amplifier), the measured output power being a measure of an amplified optical signal (the signal reflected back to the power monitor) and a ratio of the input optical power and the output optical power defining an optical gain of the optical amplifier (Kobayashi: Figures 2-6).
3). With regard to claim 10, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 8 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose wherein the major portion of the first optical signal comprises an input signal directed toward an optical amplifier and the second optical signal comprises an output amplified signal from the optical amplifier, the method further comprising the step of: determine an optical gain created in the optical amplifier from a ratio of the first electrical representation and the second electrical representation of the optical signal exiting along the far-end termination of the first fiber section.
However, first, Liu ‘205 discloses that one optical test apparatus can connected to other optical test apparatuses (Figures 5-6), and Liu ‘582 discloses “The test apparatus 10 may, for example, include a light source 20. The light source 20 may generate light (i.e. infrared light) at one or more suitable predetermined wavelengths for transmission through the other components of the test apparatus 10. … The test apparatus 10 may further include an optical connector 30. A test jumper 32 may extend from the optical connector 30. An optical fiber 34 to be tested (i.e. a fiber under test) may be connected to the optical connector 30, i.e. via the jumper 32.”, that is the light source sends optical signals to the fiber under test (34), the reflected or reversed signals from the fiber-under-test 34 is detected by the photodiode 40 in the test apparatus 10; also refer to Figure O3 above. Therefore, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests to monitor transmission (sending optical signal) and reversed (reflected back) optical signal.
Another prior art, Kobayashi et al, discloses a reflective Erbium Doped Fiber Amplifier (EDFA) (Figure 1), and Kobayashi et al discloses that the performance of the reflective EDFA is measured and calculated (page 88, Introduction), and gain efficiency is measured/obtained (Figure 2(2) and Figure 4-6). To measure the gain etc., the input optical power and output optical power need to be measured. Since the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests a bi-directional optical power monitor, which can be used to measure sending (transmission) power and reflected (or reversed) signal power, it is obvious to one skilled in the art to use the bi-directional optical power monitor to measure the gain of the reflective EDFA.
As shown in Figure 1, Kobayashi et al discloses a near-end termination of a first fiber section (the fiber for “SIGNAL INPUT”) is coupled to a bidirectional port of an optical circulator (“OPTICAL CIRCULATOR”); and a far-end termination of the second fiber section is coupled to a reflective element (“REFLECTOR” in Figure 1) for redirecting a propagating signal to propagate in a reverse direction along the second fiber section.
By combing Kobayashi et al with Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al, a system/method for measuring the performance of a reflective EDFA is obtained as Figure O4 above.
As shown in Figure O4 above, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al teaches/suggests:
a near-end termination (to the power monitor) of the first fiber section (from “OPTICAL CIRCULATOR” to the power monitor), and a far-end termination (at the “REFLECTOR”) of the second fiber section (from the power monitor to the REFLECTOR) is coupled to a reflective element (“REFLECTOR”) for redirecting a propagating signal (reflected by the REFLECTOR) to propagate in a reverse direction along the second fiber section and pass a second time through the optical power monitor prior to being coupled into the directional port of the optical circulator (Figure O4), the optical power monitor providing a measure of optical input power at the first photodiode and a measure of optical output power at the second photodiode (refer claim 8 rejection above); or the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al teaches/suggests:
wherein the major portion (the signal from the “SIGNAL INPUT”, and then reflected by the optical power monitor towards the WDM and EDF) of the first optical signal (“OPTICAL INPUT”) comprises an input signal (reflected from the optical power monitor) directed toward an optical amplifier (EDF) and the second optical signal (from the EDF to the WDM and then to the optical power monitor) comprises an output amplified signal (output from the EDF) from the optical amplifier, the method further comprising the step of: determine an optical gain created in the optical amplifier from a ratio of the first electrical representation and the second electrical representation (Kobayashi: Figures 2-6).
4). With regard to claim 15, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose an optical amplifier comprising the optical power monitor and the optical fiber of claim 1, an optical circulator, and a reflective element.
However, first, Liu ‘205 discloses that one optical test apparatus can connected to other optical test apparatuses (Figures 5-6), and Liu ‘582 discloses “The test apparatus 10 may, for example, include a light source 20. The light source 20 may generate light (i.e. infrared light) at one or more suitable predetermined wavelengths for transmission through the other components of the test apparatus 10. … The test apparatus 10 may further include an optical connector 30. A test jumper 32 may extend from the optical connector 30. An optical fiber 34 to be tested (i.e. a fiber under test) may be connected to the optical connector 30, i.e. via the jumper 32.”, that is the light source sends optical signals to the fiber under test (34), the reflected or reversed signals from the fiber-under-test 34 is detected by the photodiode 40 in the test apparatus 10; also refer to Figure O3 above. Therefore, the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests: a far-end termination of the second fiber section (“fiber under test”) is coupled to a reflective element (e.g., reflective portion/element in the “fiber under test”) for redirecting a propagating signal (from the light source 20) to propagate in a reverse direction along the second fiber section (back to the test apparatus) and pass a second time through the optical power monitor, the optical power monitor providing a measure of optical input power at the first photodiode (e.g., 50 of Liu ‘582) and a measure of optical output power at the second photodiode (e.g., 40 of Liu ‘582).
Also, another prior art, Kobayashi et al, discloses a reflective Erbium Doped Fiber Amplifier (EDFA) (Figure 1), and Kobayashi et al discloses that the performance of the reflective EDFA is measured and calculated (page 88, Introduction), and gain efficiency is measured/obtained (Figure 2(2) and Figure 4-6). To measure the gain etc., the input optical power and output optical power need to be measured. Since the combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al teaches/suggests a bi-directional optical power monitor, which can be used to measure sending (transmission) power and reflected (or reversed) signal power, it is obvious to one skilled in the art to use the bi-directional optical power monitor to measure the gain of the reflective EDFA.
As shown in Figure 1, Kobayashi et al discloses a near-end termination of a first fiber section (the fiber for “SIGNAL INPUT”) is coupled to a bidirectional port of an optical circulator (“OPTICAL CIRCULATOR”); and a far-end termination of the second fiber section is coupled to a reflective element (“REFLECTOR” in Figure 1) for redirecting a propagating signal to propagate in a reverse direction along the second fiber section.
By combing Kobayashi et al with Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al, a system/method for measuring the performance of a reflective EDFA is obtained as shown in Figure O4 above.
The combination of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al and Kobayashi et al teaches/suggests:
optical amplifier (Figure O4) comprising the optical power monitor (the power monitor in Figure O4, which is the same as Figure O3) and the optical fiber (from optical circulator to reflector) of claim 1,
an optical circulator (Optical Circulator), and a reflective element (“Reflector”), wherein: the optical circulator comprises an optical input port (for “Signal Input”) corresponding to an optical input of the optical amplifier, an optical output port (for “Signal Output”) corresponding to an optical output of the optical amplifier, and a bidirectional port (to/from the optical power monitor) that provides an optical input signal of the optical amplifier to the near-end termination (near “82”) of the first fiber section (from the Optical Circulator to the optical power monitor) of the optical fiber and receives an amplified optical output signal from the near-end terminal of the first fiber section of the optical fiber (Figure O4);
the second fiber section (from the optical power monitor to the Reflector) comprises a rare-earth doped optical fiber section (EDF) that amplifies the optical input signal as the optical input signal propagates from the near-end termination (“81”) of the second fiber section toward the far-end termination (at the Reflector) of the second fiber section (the EDF amplifies the signal from the “81” of the optical power monitor to the Reflector) and that further amplifies the optical input signal as the optical input signal propagates from the far-end termination (at the Reflector) of the second fiber section toward the near-end termination of the second fiber section (“81”);
the reflective element (“Reflector”) is coupled to the far-end termination of the second fiber section (from the optical power monitor to the Reflector) and reflects the optical input signal toward the near-end termination of the second fiber section (from the Reflector to the “81” of the power monitor);
the first photodiode of the optical power monitor (Figure O4, e.g., the photodiode at the right side of the power monitor) provides an optical power measurement of the optical input signal; and
the second photodiode (Figure O4, e.g., the photodiode at the left side of the power monitor) of the optical power monitor provides an optical power measurement of the optical output signal.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine Kobayashi et al with Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al so that the bidirectional power monitor can be used to measure the gain of a reflective EDFA quickly and conveniently.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al as applied to claim 1 above, and further in view of Galeotti et al (US 2013/0034328).
Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose the optical power monitor of claim 1, comprising a strain-relief collar surrounding the first fiber section and the second fiber section.
However, a strain-relief collar has been widely used to protect fiber. E.g., Galeotti et al discloses an optoelectronic device (Figures 1, 3-4 etc.), and a strain-relief collar (310 in Figure 3, or 410 in Figure 4) is used to surround the first fiber section (314 or 414) so to protect the fiber ([0010], [0041]-[0043], “The strain relief collar 310 and the protective tube 312 provide protection to the optical fibre 314. In particular the collar 310 provides protection at the point where the fibre enters the feed-through 308, where it is particularly vulnerable to damage”.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply a strain-relief collar as taught by Galeotti et al to the system/method of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al so that the damages to the fibers can be avoided/reduced.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al as applied to claim 1 above, and further in view of Suda et al (US 2003/0210874).
Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claim 1 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose the optical power monitor of claim 1, comprising: a first assembly housing in which are assembled the lensing arrangement and the partially reflective element; and a second assembly housing in which are assembled the first photodiode housing, the first photodiode, the second photodiode housing, and the second photodiode; and wherein second assembly housing comprises a collar termination sized to engage an inner diameter of the first assembly housing.
However, first, as shown in Figures 4A-4C, the optical power monitor comprising: a first assembly housing (tube 6) in which are assembled the lensing arrangement (7) and the partially reflective element (attached to the GRIN lens 7); and a second assembly housing (sleeve 9) in which are assembled a photodiode housing. Another prior art, Suda et al, discloses a similar module (Figures 9-10, 12, 14-16 and 17A-D etc.), in which a first assembly housing (96 in Figures 9-10; 205/200 in Figures 14-16; 304 in Figures 17A-C) in which are assembled the lensing arrangement (2 in Figure 9; 202 in Figures 14-15; 103/303 in Figure 17) and the partially reflective element (5 in Figure 9; 203 in Figures 14-16); and a second assembly housing (36 in Figures 9-10; 100/102 in Figures 14-16; 102 in Figures 17A-C) in which is assembled a photodiode housing, a first photodiode; and wherein second assembly housing comprises a collar termination (e.g. 108 in Figures 15 and 17D) sized to engage an inner diameter of the first assembly housing (Figures 15 and 17D).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Suda et al to the system/method of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al so that the assembly of the system can be made easier.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al as applied to claims 1 and 5 above, and further in view of Qin et al (US 6,603,906).
Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al disclose all of the subject matter as applied to claims 1 and 5 above. But, Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al do not expressly disclose the optical power monitor of claim 5, comprising an epoxy that covers an input enface of the dual-core capillary and secures the far-end termination of the first fiber section and the near-end termination of the second fiber section to the dual-core capillary.
However, to use epoxy to cover an input enface of fiber dual-core capillary is well known in the art. E.g., Qin et al discloses an optical power monitoring system (Figures 2-3), in which “Fiber-ferrule subassemblies employing such ferrules are manufactured by the steps of: Fabricating the ferrules to hold the optical fibers; inserting the optical fibers stripped of their polymer coating into the respective ferrule capillaries; epoxy bonding them into the ferrule capillaries, including the conical end portions” (column 1 line 57 to column 2 line 13). As shown in Figure 3, the partial semicircle at the input enface of the multi-core capillary ferrule 21 is the epoxy that covers an input enface of the multi-core capillary and secures a termination of the first fiber section and a termination of the second fiber section to the multi-core capillary.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply an epoxy as taught by Qin et al to the system/method of Liu ‘205 and Liu ‘582 and Suzuki et al and Pacala et al so that the far-end termination of the first fiber section and the near-end termination of the second fiber section can be secured to the dual-core capillary.
Conclusion
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/LI LIU/Primary Examiner, Art Unit 2634 March 21, 2026