Detailed Office Action
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Election/Restriction
Applicant’s election without traverse of claims 1-12 in the reply filed on 10 December 2025 is acknowledged.
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 of this title, 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4
Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Sugiyama, Masaki (2017/0353008; “Sugiyama”) in view of Heaton et al. (2019/0221995; “Heaton”).
Regarding claim 1, Sugiyama discloses in figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text, semiconductor embodiments of laser and wavelength locker devices, including silicon-based devices, comprising, for example, a tunable laser portion 20 configured to output an optical signal at a selected wavelength of a plurality of possible wavelengths; a wavelength locker (WLL) portion 60 configured to receive the optical signal from the tunable laser portion and facilitate locking a wavelength of the optical signal output from the tunable laser portion at the selected wavelength; an amplifier 40 configured to receive the optical signal from the tunable laser portion and amplify or attenuate the optical signal to generate an output optical signal; and an output port (not labeled but shown as arrow exiting amplifier 40 in figure 3) configured to output the output optical signal. Sugiyama, figures 3 and 5, , and related figures and text, for example, Sugiyama – Selected Text.
Sugiyama – Figures 3 and 5
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Sugiyama – Selected Text
[0031] In reference to FIG. 1, the tunable laser source according to an embodiment of the present invention is described. FIG. 1 is a schematic diagram illustrating the configuration of the tunable laser source according to the embodiment of the present invention. The tunable laser source according to the embodiment of the present invention has a semiconductor optical amplifier 2 and a resonator 3 that forms a tunable laser 1 with the semiconductor optical amplifier 2. In addition, the tunable laser source has a 2×2 type optical splitter 4 that splits part of the light outputted from the tunable laser 1, a light intensity monitor 5 into which one of the two beams that has been split from the outputted light by the optical splitter 4 is incident, and a wavelength locker 6 into which the other of the two beams that has been split from the outputted light by the optical splitter 4 is incident. The use of the 2×2 (two inputs, two outputs) type optical splitter 4 makes it possible for an optical splitter in only one stage to input light into the power monitor and the wavelength locker, and therefore, it is possible to reduce the loss in and the size of the system.
[0032] The wavelength locker 6 is formed of a waveguide that has an interferometer, and therefore has a loss to a certain degree, and thus, it is desirable for the input into the wavelength locker 6 to be greater than the input into the light intensity monitor 5. Meanwhile, the resonator 3 also has a loss of light, and therefore, the power incident into the optical splitter 4 from the semiconductor optical amplifier 2 side is greater than the power incident into the optical splitter 4 from the resonator 3 side. Accordingly, it is desirable for the outputted light that is incident into the light intensity monitor 5 to be the outputted light from the resonator 3 side split by the optical splitter 4, and for the outputted light that is incident into the wavelength locker 6 to be the outputted light from the semiconductor optical amplifier 2 side split by the optical splitter 4.
[0034] It is desirable for the resonator 3 to be a resonator that is formed of a silicon photonic wire using an SOI substrate for the purpose of miniaturization. In this case, a germanium photodiode that is formed in a germanium layer that is layered on top of a silicon layer may be used as the light intensity monitor. In the case where an SOI substrate is used, the semiconductor optical amplifier 2 made of a compound semiconductor is mounted in a region that is provided in a portion of the single crystal silicon substrate in the SOI substrate that has been dug down.
[0035] Alternatively, at least the semiconductor optical amplifier 2, the resonator 3, the optical splitter 4 and the light intensity monitor 5 may be formed of a III-V compound semiconductor such as an InGaAsP/InP-based semiconductor in a monolithic manner, which can reduce the costs for mounting.
[0036] Though the resonator 3 may have any structure, the resonator 3 may be formed of three optical waveguides, ring resonators that are provided between them as a wavelength adjusting means, and a loop mirror that is provided in the optical waveguide in the final stage as a light reflecting means. In this case, it is desirable to provide a heater for adjusting the resonating wavelength or the phase to a ring resonator or an optical waveguide.
[0037] In addition, the wavelength locker 6 may have any structure, and one example is one that splits the monitor output from the optical splitter 4 by a half mirror or a beam splitter so that the output in one direction is monitored by a photodiode and the output in the other direction is received by another photodiode through an etalon. The outputs detected by the two photodiodes are compared to detect a fluctuation in the wavelength.
[0038] According to the embodiment of the present invention, the use of the 2×2 type optical splitter 4 as an optical splitter can allow one optical splitter 4 to gain light to be incident into the light intensity monitor 5 and light to be incident into the wavelength locker 6. As a result, both a miniaturization of the tunable laser source and a reduction in the loss can be achieved.
[0039] Next, the tunable laser source according to Example 1 of the present invention is described in reference to FIGS. 2 through 5. FIG. 2 is a schematic diagram illustrating the structure of the tunable laser source according to Example 1 of the present invention, where a tunable laser is formed of a resonator 20 that is formed on an Si photonic platform 10 using an SOI substrate and an SOA 40 that is provided with an MQW active layer that works as a gain waveguide. A power monitor 50 and a wavelength locker 60 are provided on the Si photonic platform 10 and optically coupled with the tunable laser through a directional coupler 30, and all of these form a TLS chip.
[0040] FIG. 3 is a diagram illustrating the resonator formed on the Si photonic platform, which is provided with optical waveguides 21, 23 and 25 formed of an Si photonic wire sandwiched between a BOX layer made of SiO.sub.2 and an upper clad layer made of SiO.sub.2, and two ring resonators 22 and 24 having different curvature radiuses in order to gain the Vernier effect for selecting a wavelength. In addition, a loop mirror 26 is provided at the end portion of the optical waveguide 25 as a total reflection mirror. Though the size of the Si photonic wire is not particularly defined, here, the thickness is 250 nm and the width is 500 nm.
[0041] The two ring resonators 22 and 24 are provided with heaters 27 and 28 in order to carry out wavelength tuning by changing the refractive index, and a heater 29 for adjusting the phase is provided along the optical waveguide 25 in a location directly in front of the loop mirror 26. In addition, a directional coupler 30 is formed along the optical waveguide 21 with a coupling waveguide 31 arranged in proximity.
[0044] FIG. 5 is a schematic diagram illustrating the configuration of an example of a wavelength locker that is used for the tunable laser source according to Example 1 of the present invention. A wavelength locker 60 is formed of a half mirror 61, a photodiode 62 for monitoring the light output, an etalon filter 63, and a photodiode 64 for monitoring the wavelength. The monitoring light that has been incident through the coupling waveguide 31 from the directional coupler 30 is split in two by the half mirror 61. One of them enters into the photodiode 62 so as to monitor the light output. The other transmits through the etalon filter 63, and then enters into the photodiode 64. The wavelength transmission properties of the etalon filter 63 have periodicity, and therefore, in the case where the wavelength of the light outputted from the tunable laser fluctuates due to deterioration over time, the change in the wavelength is detected by the photodiode 64.
[0045] A photodiode made of a compound semiconductor is used for the power monitor 50, which is mounted in a region that has been dug out of a portion of the single crystal silicon substrate in an SOI substrate. Here, the width of the single crystal silicon layer in a portion that has extended from the coupling waveguide 31 made of an Si photonic wire may be widened, and a germanium layer may be grown on top of that so as to form a germanium photodiode, which may be used as the power monitor 50. The Si photonic platform 10 is mounted on a TEC (thermo-electric cooler) for stabilizing the temperature of the element.
Further regarding claim 1, Heaton discloses embodiments in which, “[The] integrated optical waveguide device can be on a same chip as the laser for which wavelength locking is to be performed. The integrated optical waveguide device described herein may be a monolithically integrated, compact, multi-phase optical device that can be used as a wavelength locker. In some implementations, the integrated optical waveguide device may be used to wavelength lock a laser to an arbitrary optical frequency within a wide band and, in such a case, may be fabricated together with the laser (e.g., a semiconductor laser) on a single chip.” Heaton, paragraph [0019].
Consequently, in light of Heaton’s disclosure of chip-integrated laser-locker configurations, it would have been obvious to one of ordinary skill in the art to modify Sugiyama’s embodiments to disclose a chip comprising: a tunable laser portion configured to output, to another element on the chip, an optical signal at a selected wavelength of a plurality of possible wavelengths; a wavelength locker (WLL) portion configured to receive the optical signal from the tunable laser portion and facilitate locking a wavelength of the optical signal output from the tunable laser portion at the selected wavelength; an amplifier configured to receive the optical signal from the tunable laser portion and amplify or attenuate the optical signal to generate an output optical signal; and an output port configured to output the output optical signal from the chip; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019]; because the resultant configuration would facilitate designing, fabricating, and deploying lasers integrated with wavelength lockers. Heaton, paragraphs [0021] (“[0021] Further, the integrated optical waveguide device does not include discrete optical elements and, therefore, can be smaller in size and comparatively easier to manufacture (e.g., as compared to a wavelength locker including discrete optical elements). Moreover, since the integrated optical waveguide device does not include discrete optical elements, the integrated optical waveguide device has a reduced sensitivity to vibration, and a reduced sensitivity to dust and condensation.”) and [0022] (“Additionally, the integrated optical waveguide device described herein does not suffer from hybrid integration issues (e.g., as in the case of conventional wavelength lockers that use discrete optical components) and, therefore, need not be placed in front of the laser output. As a result, locker sensitivity to external feedback is reduced and forward output of the laser is not tapped or otherwise obstructed.”).
Regarding claims 2-4, it would have been obvious to one of ordinary skill in the art to modify Sugiyama in view of Heaton, as applied in the rejection of claim 1, to disclose:
2. The chip of claim 1, wherein the WLL portion is to facilitate locking the wavelength of the optical signal output from the tunable laser portion at the selected wavelength to compensate for wavelength drift. Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
3. The chip of claim 1, wherein the WLL portion is to facilitate locking the wavelength of the optical signal output from the tunable laser portion at the selected wavelength when the selected wavelength is initially selected. Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
4. The chip of claim 1, wherein the WLL portion is to facilitate locking the wavelength of the optical signal output from the tunable laser portion at the selected wavelength when the wavelength of the optical signal is changed from a previously selected wavelength to the selected wavelength. Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
because the resultant configurations would facilitate designing, fabricating, and deploying lasers integrated with wavelength lockers. Heaton, paragraphs [0021] and [0022].
Claims 5-6 and 9-12
Claims 5-6 and 9-12 are rejected under 35 U.S.C. 103 as being unpatentable over Sugiyama, Masaki (2017/0353008; “Sugiyama”) in view of Heaton et al. (2019/0221995; “Heaton”), as applied in the rejection of claims 1-4, and further in view of Parker et al. (2018/0100967; “Parker”).
Regarding claims 5-6 and 9-12, Parker discloses in figures 5 and 10, and related figures and text, for example, Parker – Selected Text, photonic integrated circuits comprising athermal Mach interferometers and silicon-based photodiodes. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text.
Parker – Selected Text
[0016] FIG. 5A is a graph of the filter transmission as a function of relative wavelength at temperatures of 30° C., 53° C., and 85° C., respectively, for a silicon/silicon-nitride-(Si/SiNx)-based athermal AMZI in accordance with various embodiments.
[0072] With reference to FIG. 10A, implementation of a PIC 1000 on an SOI substrate 1002 (which includes layers of silicon, silicon oxide, and silicon) is shown in cross-sectional view. The top silicon layer 1004 of the SOI substrate 1002 is patterned and then partially etched to form the waveguides and other integrated optical structures 1006 of the AMZI (including the output coupler) in region 1007 and of a laser diode and associated modulator (used to send data and optionally apply a low frequency dither signal to the laser) and photodiodes (serving as the detectors) in region 1008. The laser can be tuned using semiconductor material in region 1008 to exploit linear and/or quadratic electro-optic effects or carrier injection (via free carrier absorption, bandgap shrinkage, band filling effects), or by a thermal tuning element in region 1007 placed within the laser cavity. The output coupler may be, for example, an MMI that takes the form of a rectangle (in top view, e.g., as shown in FIG. 3A) that merges into the (narrower, and optionally tapered) waveguides at the input and output ports. The dimensions of the rectangular MMI and the positions of the inputs and outputs are chosen such that specified phase shifts are imparted between the two waves originating at the input ports and interfering at one of the outputs; these phase shifts generally differ between the output ports. For a 90-degree hybrid receiver, for example, the output coupler may be configured such that the phase shifts between the two interfering signals are 0°, 90°, 180°, and 270° at the four output ports, respectively. (The same filter-phase information can be obtained if the four relative phase shifts are all shifted by the same additional phase offset.) On top of the patterned and etched silicon layer, an insulating layer of silicon-oxide may be deposited to form a cladding 1010. In the region 1008 of the laser and detectors, on top of the cladding 1010 above the integrated optical structures of these components, compound semiconductor material 1012 including n-doped and p-doped regions is deposited to form the laser diodes, modulators, and photodiodes; typically, the compound semiconductor includes multiple different materials bonded to the surface and optimized for each function. Pad metal and metal contacts (not shown) are deposited to facilitate applying a current through the laser diode to cause stimulated emission, applying a current or voltage to laser tuning elements, generating a variable electric field across the modulator to transmit data and optionally provide dither for the wavelength locker, and measuring currents generated in the photodiodes. Light created in the laser diode is coupled into the integrated optical structures beneath, which may form a resonant cavity with an output coupler leading to the modulator, optional optical switches and power dividers, and then the input of the AMZI. Light from the output ports of the output coupler of the wavelength locker is coupled into the compound semiconductor of the photodiodes.
Consequently, it would have been obvious to one of ordinary skill in the art to modify Sugiyama in view of Heaton, as applied in the rejection of claims 1-4, to disclose:
5. The chip of claim 1, wherein the tunable laser portion includes a silicon photodiode configured to facilitate tuning of the optical signal to the selected wavelength. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
6. The chip of claim 5, wherein the silicon photodiode is further configured to facilitate alteration of an amplitude of the optical signal. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
9. The chip of claim 1, wherein the WLL portion includes an athermal mach-zehnder interferometer (MZI). Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
10. The chip of claim 1, wherein the WLL portion includes a first silicon photodiode and a second silicon photodiode, wherein the locking of the wavelength of the optical signal at the selected wavelength is based on feedback generated by the WLL based on a first measurement of the wavelength of the optical signal at the first silicon photodiode and a second measurement of the wavelength of the optical signal at the second silicon photodiode. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
11. The chip of claim 10, wherein the feedback is based on a comparison of the first measurement and the second measurement. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
12. The chip of claim 10, wherein the tunable laser portion includes a phase tuner configured to change, based on the feedback, a wavelength of the optical signal within the tunable laser portion prior to provision of the optical signal to the WLL. Parker, figures 5 and 10, and related figures and text, for example, Parker – Selected Text; Sugiyama, figures 3 and 5, and related figures and text, for example, Sugiyama – Selected Text; Heaton, paragraph [0019].
because the resultant configurations would facilitate designing, fabricating, and deploying compact lasers integrated with wavelength lockers. Parker, abstract; Heaton, paragraphs [0021] and [0022].
Claim 7
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Sugiyama, Masaki (2017/0353008; “Sugiyama”) in view of Heaton et al. (2019/0221995; “Heaton”), as applied in the rejection of claims 1-4, and further in view of Blumenthal, Daniel Jacob (2015/0333475; “Blumenthal”).
Regarding claim 7, Blumenthal discloses in figure 1, and related text, an integrated laser configuration in which the optical amplifier is positioned between the laser’s front mirror and the output port. Blumenthal, figure 1 and paragraph [0045].
Blumenthal – Figure 1
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Consequently, it would have been obvious to one of ordinary skill in the art to modify Sugiyama in view of Heaton, as applied in the rejection of claims 1-4, such that the optical signal is output from a front mirror of the tunable laser portion to the amplifier; Blumenthal, figure 1 and paragraph [0045]; because the resultant configurations would facilitate designing, fabricating, and deploying compact lasers monolithically integrated with wavelength lockers. Blumenthal, paragraph [0045]; Heaton, paragraphs [0021] and [0022].
Claim 8
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Sugiyama, Masaki (2017/0353008; “Sugiyama”) in view of Heaton et al. (2019/0221995; “Heaton”), as applied in the rejection of claims 1-4, and further in view of Parker et al. (2018/0100967; “Parker”), as applied in the rejection of claims 5-6 and 9-12; and further in view of Wilmart et al. (2020/0161831; “Wilmart”).
Regarding claim 8, Wilmart discloses in paragraphs [0122], [0126], [0131], [0156], [0175], and [0177] that it would be obvious to one of ordinary skill in the art that athermal mach-zehnder interferometers (MZI) and athermal silicon microring resonators are design choices yielding predictable results when integrated with semiconductor laser configurations.
Consequently, it would have been obvious to one of ordinary skill in the art to modify Sugiyama in view of Heaton, as applied in the rejection of claims 1-4, and further in view of Parker, and further in view of Wilmart, as applied in the rejection of claims 5-6 and 9-12, such that the WLL portion includes an athermal ring resonator; Wilmart, paragraphs [0122], [0126], [0131], [0156], [0175], and [0177]; because the resultant configuration would facilitate designing, fabricating, and deploying compact lasers integrated with wavelength lockers. Parker, abstract; Heaton, paragraphs [0021] and [0022].
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER RADKOWSKI whose telephone number is (571)270-1613. The examiner can normally be reached on M-Th 9-5. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Thomas Hollweg, can be reached on (571) 270-1739. The fax phone number for the organization where this application or proceeding is assigned is (571) 273-8300.
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/PETER RADKOWSKI/Primary Examiner, Art Unit 2874