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 .
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claim 1-20 rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the enablement requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to enable one skilled in the art to which it pertains, or with which it is most nearly connected, to make and/or use the invention.
The Examiner notes that -60db is 1/million in power i.e. -60db is a fraction, not a unit of power, see that an Interview was conducted on 2/4/26, the proposed amendment of "having an associated active area, wherein the avalanche photodiode is to maintain a spot with a width of approximately -40 to -60db at an anode ring level" was discussed during which the Examiner then asked the Applicant what the new limitation "-40 to -60db" means and noted that if the fiber is moved closer to the photodiode, or if the anode ring diameter was increased, then the light input to the photodiode would increase and the Examiner asked does this mean that the distance of the fiber from the photodiode or the anode ring diameter are result effective variables for the new claim limitation of "-40 to -60db" for case law Aller. The Applicant stated that they are not result effective variables and that the "-40 to -60db" limitation is a minimum power that is required for the APD to function. The Examiner responded that dB stands for decibel and is a fraction and asked the Applicant what is "-40 to -60db" a fraction of ? However the Applicant responded that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function. The Examiner again stated that decibel is only a fraction and not a unit of power, and since the Applicant responded that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function, thus the Examiner has provided this 112 enablement rejection because "-40 to -60db" is not an actual power level and clearly the actual power is dependent on how much light is input from the other end of the fiber, thus the Applicant’s statement that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function means that the invention is not enabled.
Note: For all claims, the Examiner notes a fact known to a person of ordinary skill in the art namely that a single mode fiber output is Gaussian, see google search result:
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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.
The factual inquiries 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.
Note:- The Examiner notes that -60db is a fraction of 1/thousand in amplitude and 1/million in power .
Claim(s) 1 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (US 20160308075 A1) hereafter referred to as Wang in view of Himeno (see PTO-892 filed 12/10/2025)
In regard to claim 1 Wang teaches [see paragraph 0227 “FIG. 48 is a diagram showing some aspects of a flip chip arrangement for a MS-PD/APD integrated with a TIA and/or another signal processing IC on a single silicon chip, according to some other embodiments”] an optical device, comprising:
an avalanche photodiode [“MS-PD/APD”] having an [i.e. the active area of the “MS-PD/APD”, see plurality of examples of “microstructured photodiode(s)/avalanche photodiode(s) MS-PD/APD”] active area,
an optical fiber, wherein [“optical fiber 4524 can then be inserted into the via 4626 such that it provides a guide to align the fiber 4524 to the MS-PD/APD 4520 thereby simplifying the optical packing and alignment of the optical fiber to the MS-PD/APD with a cost reduction of approximately 30% or greater. According to some embodiments, the fiber 4524 may be also be tapered and/or the via 4626 may have multiple diameters such that it provides a stop for the fiber 4524. For example, a step in the via 4626 is provided such that the edge of the fiber 4524 can rest on the step, where it can be attached to the silicon. This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”] the optical fiber is butt- coupled to the avalanche photodiode, and wherein an index-matching material is inserted [“According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”] between the optical fiber and the avalanche photodiode.
but does not teach “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level ” and “having a trench-assisted step index structure”.
The Examiner notes that -60db is 1/million in power i.e. the new limitation is stating that essentially all the light power in the fiber is input to the photodiode, see that an Interview was conducted on 2/4/26, the proposed amendment of "having an associated active area, wherein the avalanche photodiode is to maintain a spot with a width of approximately -40 to -60db at an anode ring level" was discussed during which the Examiner then asked the Applicant what the new limitation "-40 to -60db" means and noted that if the fiber is moved closer to the photodiode, or if the anode ring diameter was increased, then the light input to the photodiode would increase and the Examiner asked does this mean that the distance of the fiber from the photodiode or the anode ring diameter are result effective variables for the new claim limitation of "-40 to -60db" for case law Aller. The Applicant stated that they are not result effective variables and that the "-40 to -60db" limitation is a minimum power that is required for the APD to function. The Examiner responded that dB stands for decibel and is a fraction and asked the Applicant what is "-40 to -60db" a fraction of ? However the Applicant responded that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function. The Examiner again stated that decibel is only a fraction and not a unit of power, thus the Examiner notes that the distance of the fiber from the photodiode or the anode ring diameter are both result effective variables for light input to the photodiode.
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However see Himeno Fig. 3 , the index shape in the fiber, see reproduced above, see trench and step, is known to have a low Bending loss, see analysis and design.
Thus, it 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 to modify Wang to include having a trench-assisted step index structure.
Thus it would be obvious to combine the references to arrive at the claimed limitation.
The motivation is for good control of light and that this type of fiber is known in the art to have low Bending loss for good reliability.
Wang and Himeno as combined does not teach “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level ”.
However see Wang “This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”, “According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”
See Wang teaches “anode ring” and device structure see examples in Fig. 10 see paragraph 0186 “P ohmic contact, anode 1028” “optical signal impinges onto the microstructured photodiode 1060 either at normal incidence or at an angle to normal incidence” see also Fig. 8B light is shown, Fig. 78 “N and P contacts 7828 and 7830 can both be on the front side. The P contact can also be on the backside on the P Si substrate, as in contact 7832”, see light is shown.
Thus, it 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 to modify Wang to include “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level ”.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is anode ring is to make good electrical contact at the anode and adjusting the distance of the fiber from the photodiode and/or the anode ring diameter to best optimize light absorption in the APD without wasting space i.e. without too much area for the APD.
Claim(s) 2-5, 7, 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Himeno as combined and further in view of Chen et al. (US 20160327735 A1) hereafter referred to as Chen
In regard to claim 2 Wang and Himeno as combined does not specifically teach wherein the optical fiber includes a face that includes an angle of less than approximately 85° and greater than approximately 70° relative to a central axis of the optical fiber.
See that this type of analysis is common in the art, see Chen teaches a butt-coupled photodetector, see paragraph 0031, see Fig. 1A shown below and compare to the instant Application Fig. 4A on the right,
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see Chen paragraph 0034, see how to avoid residual reflection back to the fiber core “An end 105 of the HC-PCF 104 can be normal-cleaved or angle-cleaved. FIG. 1A shows an angle-cleaved end 105. The detector surface 110 is preferably antireflective (AR) coated to reduce back reflection, and can be normal to the fiber axis 111 or tilted at an angle to avoid residual reflection back to the fiber core. The orientation of this tilt can be parallel or anti-parallel to the angle-cleaved fiber end surface”, see the geometry “... when the detector 110 is 1 mm away from the fiber end 105. In practice, the detector 109 is preferably even closer to the fiber end in order to catch essentially all the light out of the fiber. The detector 109 area D can be made large enough (e.g., ˜100 μm dia.) to catch the light ...”, see “placing the photo-detector surface 109 of a photodetector 110 close to the output end of the HC-PCF 104 (with hollow core 106) so that the fiber modes remain orthogonal to each other on the detector surface 109”.
Thus, it 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 to modify Wang to include wherein the optical fiber includes a face that includes a non perpendicular angle relative to a central axis of the optical fiber.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that these are standard design parameters which rely on Snell’s law of refraction and and it is standard practice to consider them for best coupling of light with low reflection to the core.
Wang, Himeno and Chen as combined does not specifically teach “less than approximately 85° and greater than approximately 70°”.
However the dimensions of the structure, the angles of the light and the refractive indices are known, and the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “less than approximately 85° and greater than approximately 70°”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
In regard to claim 3 Wang, Himeno and Chen as combined does not specifically teach wherein an active area of a chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber, or the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber.
See rejection claim 2, the dimensions of the structure, the angles of the light and the refractive indices are known, and the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “wherein an active area of a chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber, or the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
In regard to claim 4 Wang, Himeno and Chen as combined teaches wherein the optical fiber includes an angled face [see combination Chen see Chen Fig. 1A reproduced above], and wherein an active area of a chip associated with the avalanche photodiode is positioned at an angle relative to [see combination Chen see Chen Fig. 1A reproduced above] the angled face to permit, for an incident light beam from the optical fiber, redirection, [see combination Chen see Chen Fig. 1A reproduced above] away from the active area of the chip, of the incident light beam that is first reflected [see combination Chen see Chen Fig. 1A reproduced above, this is basic geometry, see that light output has an angular distribution, see that in Chen motivation is best coupling of light with low reflection to the core] onto the avalanche photodiode and secondly reflected onto an optical fiber surface.
In regard to claim 5 Wang, Himeno and Chen as combined teaches wherein the optical fiber is index-matched [see Wang index matching] relative to an active area of a chip associated with the avalanche photodiode.
In regard to claim 7 Wang, Himeno and Chen as combined does not specifically teach wherein for a 30μm wide chip associated with the avalanche photodiode, a core of the optical fiber is disposed at less than 20μm from an active area of the 30μm wide chip, or approximately 20μm from the active area of the 30μm wide chip.
However see claim 1 adjusting the distance of the fiber from the photodiode and/or the anode ring diameter to best optimize light absorption in the APD without wasting space i.e. without too much area for the APD, see the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “wherein for a 30μm wide chip associated with the avalanche photodiode, a core of the optical fiber is disposed at less than 20μm from an active area of the 30μm wide chip, or approximately 20μm from the active area of the 30μm wide chip”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
In regard to claim 8 Wang, Himeno and Chen as combined does not specifically teach wherein for a 50μm wide chip associated with the avalanche photodiode, the optical fiber includes a face that is disposed at less than 40μm from an active area of the 50μm wide chip, or approximately 40μm from the active area of the 50 μm wide chip.
However see claim 1 adjusting the distance of the fiber from the photodiode and/or the anode ring diameter to best optimize light absorption in the APD without wasting space i.e. without too much area for the APD, and the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “wherein for a 50μm wide chip associated with the avalanche photodiode, the optical fiber includes a face that is disposed at less than 40μm from an active area of the 50μm wide chip, or approximately 40μm from the active area of the 50 μm wide chip”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang, Himeno and Chen as combined and further in view of Haddad et al. (US 20200401781 A1) hereafter referred to as Haddad
In regard to claim 6 Wang, Himeno and Chen as combined does not specifically teach wherein the optical fiber includes an intermediate pin-hole to truncate a Gaussian beam relative to an active area of a chip associated with the avalanche photodiode.
However these optical components are common in the art, see Haddad Fig. 6 see paragraph 0079 “Each of the component fibers 625 is optically coupled to one of the pinholes 611 and one of the photosensors of the photosensor array 622” “The fiber-optic taper 623 is optically coupled to the photosensor array 622 via optical index matching material (e.g., optical cement) or some other coupling medium” “The pinhole array 610 serves to collimate light rays reflected by the contact surface 604a to preferentially select rays at an angle greater than or equal to critical angle, Θ.sub.c, such that the selected light rays are communicated to the array of photosensors 622”.
Thus, it 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 to modify Wang to include wherein the optical fiber includes an intermediate pin-hole to truncate a Gaussian beam relative to an active area of a chip associated with the avalanche photodiode.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that pinhole is well known to select desired angles range of light from fiber for detection by blocking undesired light.
Claim(s) 9, 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (US 20160308075 A1) hereafter referred to as Wang in view of Himeno (see PTO-892 filed 12/10/2025)
In regard to claim 9 Wang teaches [see paragraph 0227 “FIG. 48 is a diagram showing some aspects of a flip chip arrangement for a MS-PD/APD integrated with a TIA and/or another signal processing IC on a single silicon chip, according to some other embodiments”] an apparatus, comprising:
an avalanche photodiode [“MS-PD/APD”] having an active area [i.e. the active area of the “MS-PD/APD”, see plurality of examples of “microstructured photodiode(s)/avalanche photodiode(s) MS-PD/APD”],
an optical fiber [“optical fiber 4524”], wherein the optical fiber is butt- coupled [“optical fiber 4524 can then be inserted into the via 4626 such that it provides a guide to align the fiber 4524 to the MS-PD/APD 4520 thereby simplifying the optical packing and alignment of the optical fiber to the MS-PD/APD with a cost reduction of approximately 30% or greater. According to some embodiments, the fiber 4524 may be also be tapered and/or the via 4626 may have multiple diameters such that it provides a stop for the fiber 4524. For example, a step in the via 4626 is provided such that the edge of the fiber 4524 can rest on the step, where it can be attached to the silicon. This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”] to the avalanche photodiode, and wherein an index-matching material is inserted [“According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”] between the optical fiber and the avalanche photodiode, and
wherein a face of the optical fiber includes at least one of a specified angle relative to or a specified distance [“This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”] from an active area of a chip associated with the avalanche photodiode,
but does not teach “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level” and “having a trench-assisted step index structure” and does not state “to minimize a tailing associated with an incident light beam from the optical fiber”.
The Examiner notes that -60db is 1/million in power i.e. the new limitation and the “tailing” limitation are stating that essentially all the light power in the fiber is input to the photodiode, see that an Interview was conducted on 2/4/26, the proposed amendment of "having an associated active area, wherein the avalanche photodiode is to maintain a spot with a width of approximately -40 to -60db at an anode ring level" was discussed during which the Examiner then asked the Applicant what the new limitation "-40 to -60db" means and noted that if the fiber is moved closer to the photodiode, or if the anode ring diameter was increased, then the light input to the photodiode would increase and the Examiner asked does this mean that the distance of the fiber from the photodiode or the anode ring diameter are result effective variables for the new claim limitation of "-40 to -60db" for case law Aller. The Applicant stated that they are not result effective variables and that the "-40 to -60db" limitation is a minimum power that is required for the APD to function. The Examiner responded that dB stands for decibel and is a fraction and asked the Applicant what is "-40 to -60db" a fraction of ? However the Applicant responded that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function. The Examiner again stated that decibel is only a fraction and not a unit of power, thus the Examiner notes that the distance of the fiber from the photodiode or the anode ring diameter are both result effective variables for light input to the photodiode.
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However see Himeno Fig. 3 , the index shape in the fiber, see reproduced above, see trench and step, is known to have a low Bending loss, see analysis and design.
Thus, it 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 to modify Wang to include having a trench-assisted step index structure.
Thus it would be obvious to combine the references to arrive at the claimed limitation.
The motivation is for good control of light and that this type of fiber is known in the art to have low Bending loss for good reliability.
Wang and Himeno as combined does not teach “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level” and does not state “to minimize a tailing associated with an incident light beam from the optical fiber”.
However see Wang “This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”, “According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”
See Wang teaches “anode ring” and device structure see examples in Fig. 10 see paragraph 0186 “P ohmic contact, anode 1028” “optical signal impinges onto the microstructured photodiode 1060 either at normal incidence or at an angle to normal incidence” see also Fig. 8B light is shown, Fig. 78 “N and P contacts 7828 and 7830 can both be on the front side. The P contact can also be on the backside on the P Si substrate, as in contact 7832”, see light is shown.
Thus, it 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 to modify Wang to include “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level” and “to minimize a tailing associated with an incident light beam from the optical fiber”.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is anode ring is to make good electrical contact at the anode and adjusting the distance of the fiber from the photodiode and/or the anode ring diameter to best optimize light absorption in the APD without wasting space i.e. without too much area for the APD.
In regard to claim 13 Wang and Himeno as combined teaches wherein the optical fiber is index-matched [see Wang teaches index matching] relative to the active area of the chip associated with the avalanche photodiode.
Claim(s) 10-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Himeno as combined and further in view of Chen et al. (US 20160327735 A1) hereafter referred to as Chen
In regard to claim 10 Wang and Himeno as combined does not specifically teach wherein the face of the optical fiber includes the specified angle of less than approximately 85° and greater than approximately 70° relative to a central axis of the optical fiber.
See Chen teaches a butt-coupled photodetector, see paragraph 0031, see Fig. 1A shown below and compare to the instant Application Fig. 4A on the right,
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see Chen paragraph 0034, see how to avoid residual reflection back to the fiber core “An end 105 of the HC-PCF 104 can be normal-cleaved or angle-cleaved. FIG. 1A shows an angle-cleaved end 105. The detector surface 110 is preferably antireflective (AR) coated to reduce back reflection, and can be normal to the fiber axis 111 or tilted at an angle to avoid residual reflection back to the fiber core. The orientation of this tilt can be parallel or anti-parallel to the angle-cleaved fiber end surface”, see the geometry “... when the detector 110 is 1 mm away from the fiber end 105. In practice, the detector 109 is preferably even closer to the fiber end in order to catch essentially all the light out of the fiber. The detector 109 area D can be made large enough (e.g., ˜100 μm dia.) to catch the light ...”, see “placing the photo-detector surface 109 of a photodetector 110 close to the output end of the HC-PCF 104 (with hollow core 106) so that the fiber modes remain orthogonal to each other on the detector surface 109”.
It is noted that the angles of the light and the refractive indices are known, and the light obeys Snell’s law.
Thus, it 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 to modify Wang to include wherein the face of the optical fiber includes the specified angle of less than approximately 85° and greater than approximately 70° relative to a central axis of the optical fiber.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that these are standard design parameters which rely on Snell’s law of refraction and and it is standard practice to consider them during optimization for best coupling of light with low reflection to the core.
In regard to claim 11 Wang, Himeno and Chen as combined does not specifically teach wherein the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber, or the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber.
See combination Chen paragraph 0034, see how to avoid residual reflection back to the fiber core, see the dimensions of the structure, the angles of the light and the refractive indices are known, and the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “wherein the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber, or the active area of the chip associated with the avalanche photodiode is positioned at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
In regard to claim 12 Wang, Himeno and Chen as combined teaches wherein the at least one of the specified angle [see combination Chen see Chen Fig. 1A reproduced above] or the specified distance permits, for the incident light beam from the optical fiber, redirection [see combination Chen see Chen Fig. 1A reproduced above], away from the active area of the chip, of the incident light beam that is first reflected [see combination Chen see Chen Fig. 1A reproduced above, this is basic geometry, see that light output has an angular distribution, see that in Chen motivation is best coupling of light with low reflection to the core ] onto the avalanche photodiode and secondly reflected onto an optical fiber surface.
Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang, Himeno and Chen as combined and further in view of Haddad et al. (US 20200401781 A1) hereafter referred to as Haddad
In regard to claim 14 Wang, Himeno and Chen as combined does not specifically teach wherein the optical fiber includes an intermediate pin-hole to truncate a Gaussian beam relative to the active area of the chip associated with the avalanche photodiode.
However these optical components are common in the art, see Haddad Fig. 6 see paragraph 0079 “Each of the component fibers 625 is optically coupled to one of the pinholes 611 and one of the photosensors of the photosensor array 622” “The fiber-optic taper 623 is optically coupled to the photosensor array 622 via optical index matching material (e.g., optical cement) or some other coupling medium” “The pinhole array 610 serves to collimate light rays reflected by the contact surface 604a to preferentially select rays at an angle greater than or equal to critical angle, Θ.sub.c, such that the selected light rays are communicated to the array of photosensors 622”.
Thus, it 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 to modify Wang to include wherein the optical fiber includes an intermediate pin-hole to truncate a Gaussian beam relative to the active area of the chip associated with the avalanche photodiode.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that pinhole is well known to select desired angles range of light from fiber for detection by blocking undesired light.
Claim(s) 15, 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (US 20160308075 A1) hereafter referred to as Wang in view of Himeno (see PTO-892 filed 12/10/2025)
In regard to claim 15 Wang teaches [see paragraph 0227 “FIG. 48 is a diagram showing some aspects of a flip chip arrangement for a MS-PD/APD integrated with a TIA and/or another signal processing IC on a single silicon chip, according to some other embodiments”] a method for butt-coupling an avalanche photodiode comprising:
coupling an optical fiber [“optical fiber 4524”] to an avalanche photodiode [“MS-PD/APD”] by butt-coupling [“optical fiber 4524 can then be inserted into the via 4626 such that it provides a guide to align the fiber 4524 to the MS-PD/APD 4520 thereby simplifying the optical packing and alignment of the optical fiber to the MS-PD/APD with a cost reduction of approximately 30% or greater. According to some embodiments, the fiber 4524 may be also be tapered and/or the via 4626 may have multiple diameters such that it provides a stop for the fiber 4524. For example, a step in the via 4626 is provided such that the edge of the fiber 4524 can rest on the step, where it can be attached to the silicon. This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”] the optical fiber to the avalanche photodiode having an active area [i.e. the active area of the “MS-PD/APD”, see plurality of examples of “microstructured photodiode(s)/avalanche photodiode(s) MS-PD/APD”],
wherein an index-matching material is inserted [“According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”] between the optical fiber and the avalanche photodiode,
wherein a face of the optical fiber includes at least one of a specified angle relative to or a specified distance [“This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”] from an active area of a chip associated with the avalanche photodiode; and
but does not teach “having a trench-assisted step index structure” and “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level”, and does not state “specifying the at least one of the specified angle or the specified distance to minimize a tailing associated with an incident light beam from the optical fiber”.
The Examiner notes that -60db is 1/million in power i.e. the new limitation and the “tailing” limitation are stating that essentially all the light power in the fiber is input to the photodiode, see that an Interview was conducted on 2/4/26, the proposed amendment of "having an associated active area, wherein the avalanche photodiode is to maintain a spot with a width of approximately -40 to -60db at an anode ring level" was discussed during which the Examiner then asked the Applicant what the new limitation "-40 to -60db" means and noted that if the fiber is moved closer to the photodiode, or if the anode ring diameter was increased, then the light input to the photodiode would increase and the Examiner asked does this mean that the distance of the fiber from the photodiode or the anode ring diameter are result effective variables for the new claim limitation of "-40 to -60db" for case law Aller. The Applicant stated that they are not result effective variables and that the "-40 to -60db" limitation is a minimum power that is required for the APD to function. The Examiner responded that dB stands for decibel and is a fraction and asked the Applicant what is "-40 to -60db" a fraction of ? However the Applicant responded that "-40 to -60db" is an actual power level specifying the minimum power below which the APD would not function. The Examiner again stated that decibel is only a fraction and not a unit of power, thus the Examiner notes that the distance of the fiber from the photodiode or the anode ring diameter are both result effective variables for light input to the photodiode.
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However see Himeno Fig. 3 , the index shape in the fiber, see reproduced above, see trench and step, is known to have a low Bending loss, see analysis and design.
Thus, it 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 to modify Wang to include having a trench-assisted step index structure.
Thus it would be obvious to combine the references to arrive at the claimed limitation.
The motivation is for good control of light and that this type of fiber is known in the art to have low Bending loss for good reliability.
Wang and Himeno as combined does not teach “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level”, and does not state “specifying the at least one of the specified angle or the specified distance to minimize a tailing associated with an incident light beam from the optical fiber”.
However see Wang “This step arrangement also provides a precise distance between the fiber and the MS-PD/APD for optimal light collection”, “According to some embodiments, index matching fluid, gel and/or polymer and/or dielectric bulk or thin film may be used in the via 4626, particularly in the space between the fiber 4524 and the MS-PD/APD 4520 to optimize the transfer of optical signal from the fiber to the MS-PD/APD”
See Wang teaches “anode ring” and device structure see examples in Fig. 10 see paragraph 0186 “P ohmic contact, anode 1028” “optical signal impinges onto the microstructured photodiode 1060 either at normal incidence or at an angle to normal incidence” see also Fig. 8B light is shown, Fig. 78 “N and P contacts 7828 and 7830 can both be on the front side. The P contact can also be on the backside on the P Si substrate, as in contact 7832”, see light is shown.
Thus, it 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 to modify Wang to include “wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level”, and “specifying the at least one of the specified angle or the specified distance to minimize a tailing associated with an incident light beam from the optical fiber”.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is anode ring is to make good electrical contact at the anode and adjusting the distance of the fiber from the photodiode and/or the anode ring diameter to best optimize light absorption in the APD without wasting space i.e. without too much area for the APD.
In regard to claim 19 Wang and Himeno as combined teaches further comprising: index-matching [see Wang teaches index matching] the optical fiber relative to the active area of the chip associated with the avalanche photodiode.
Claim(s) 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Himeno as combined and further in view of Chen et al. (US 20160327735 A1) hereafter referred to as Chen
In regard to claim 16 Wang and Himeno as combined does not specifically teach further comprising:specifying the face of the optical fiber to include the specified angle of less than approximately 85° and greater than approximately 70° relative to a central axis of the optical fiber.
See Chen teaches a butt-coupled photodetector, see paragraph 0031, see Fig. 1A shown below and compare to the instant Application Fig. 4A on the right,
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see Chen paragraph 0034, see how to avoid residual reflection back to the fiber core “An end 105 of the HC-PCF 104 can be normal-cleaved or angle-cleaved. FIG. 1A shows an angle-cleaved end 105. The detector surface 110 is preferably antireflective (AR) coated to reduce back reflection, and can be normal to the fiber axis 111 or tilted at an angle to avoid residual reflection back to the fiber core. The orientation of this tilt can be parallel or anti-parallel to the angle-cleaved fiber end surface”, see the geometry “... when the detector 110 is 1 mm away from the fiber end 105. In practice, the detector 109 is preferably even closer to the fiber end in order to catch essentially all the light out of the fiber. The detector 109 area D can be made large enough (e.g., ˜100 μm dia.) to catch the light ...”, see “placing the photo-detector surface 109 of a photodetector 110 close to the output end of the HC-PCF 104 (with hollow core 106) so that the fiber modes remain orthogonal to each other on the detector surface 109”.
It is noted that the angles of the light and the refractive indices are known, and the light obeys Snell’s law.
Thus, it 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 to modify Wang to include further comprising:specifying the face of the optical fiber to include the specified angle of less than approximately 85° and greater than approximately 70° relative to a central axis of the optical fiber.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that these are standard design parameters which rely on Snell’s law of refraction and and it is standard practice to consider them during optimization for best coupling of light with low reflection to the core.
In regard to claim 17 Wang, Himeno and Chen as combined does not specifically teach further comprising: positioning the active area of the chip associated with the avalanche photodiode at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber; or positioning the active area of the chip associated with the avalanche photodiode at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber.
See combination Chen paragraph 0034, see how to avoid residual reflection back to the fiber core, see the dimensions of the structure, the angles of the light and the refractive indices are known, and the light obeys Snell’s law, thus both the transmitted light and reflected light are known thus it 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 to use “further comprising: positioning the active area of the chip associated with the avalanche photodiode at an angle of greater than approximately 93° and less than approximately 98° relative to a central axis of the optical fiber; or positioning the active area of the chip associated with the avalanche photodiode at an angle of greater than approximately 97° and less than approximately 110° relative to the central axis of the optical fiber”, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or working ranges involves only routine skill in the art. In re Aller, 105 USPQ 233
In regard to claim 18 Wang, Himeno and Chen as combined teaches further comprising: specifying the at least one of the specified angle [see combination Chen see Chen Fig. 1A reproduced above] or the specified distance to permit, for the incident light beam from the optical fiber, redirection [see combination Chen see Chen Fig. 1A reproduced above], away from the active area of the chip, of the incident light beam that is first reflected [see combination Chen see Chen Fig. 1A reproduced above, this is basic geometry, see that light output has an angular distribution, see that in Chen motivation is best coupling of light with low reflection to the core ] onto the avalanche photodiode and secondly reflected onto an optical fiber surface.
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang, Himeno and Chen as combined and further in view of Haddad et al. (US 20200401781 A1) hereafter referred to as Haddad
In regard to claim 20 Wang, Himeno and Chen as combined does not specifically teach further providing:implementing, for the optical fiber, an intermediate pin-hole to truncate a Gaussian beam relative to the active area of the chip associated with the avalanche photodiode.
However these optical components are common in the art, see Haddad Fig. 6 see paragraph 0079 “Each of the component fibers 625 is optically coupled to one of the pinholes 611 and one of the photosensors of the photosensor array 622” “The fiber-optic taper 623 is optically coupled to the photosensor array 622 via optical index matching material (e.g., optical cement) or some other coupling medium” “The pinhole array 610 serves to collimate light rays reflected by the contact surface 604a to preferentially select rays at an angle greater than or equal to critical angle, Θ.sub.c, such that the selected light rays are communicated to the array of photosensors 622”.
Thus, it 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 to modify Wang to include further providing:implementing, for the optical fiber, an intermediate pin-hole to truncate a Gaussian beam relative to the active area of the chip associated with the avalanche photodiode.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is that pinhole is well known to select desired angles range of light from fiber for detection by blocking undesired light.
Response to Arguments
Applicant's arguments filed 2/24/26 have been fully considered but they are not persuasive.
Applicant’s arguments with respect to claim(s) 1-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
On page 12, 13 the Applicant argues that Kurata does not teach Avalanche photodiode, however see Non-Final rejection Kurata teaches “an avalanche photodiode [see column 8 line 6 “when the optical semiconductor element is implemented by an avalanche photodiode or similar photodetector, the refraction index matching substance reduces the difference in refraction index between the core of the fiber and the outside as well as the difference in refraction between the light-sensitive surface of the photodetector and the outside”] ”.
On page 13, 14 the Applicant argues “Applicant submits that the Office Action has not provided sufficient motivation to combine Kurata and Himeno references. In particular, there appears to be no suggestion to combine implementing optical coupling equipment for an optical semiconductor and an optical fiber (per Kurata) with designing and manufacturing for three types of fibers-a step-index-profile fiber, a trench-index-profile fiber, and a holey fiber (per Himeno). Without suitable rationale, a prima facie case of obviousness does not exist. If a sufficient motivation to combine has not been shown, an obviousness rejection may not be supported using the combination of prior art elements rationale, and such a rejection should be withdrawn. Therefore, Applicants respectfully request that the rejection be withdrawn”.
The Examiner responds that in the current rejection uses fiber in both primaray and secondary reference and a person of ordinary skill inthe art is able to understand how using a superior fiber of a secondary reference gives benefit to the equipment taught by the primary reference and that the function of the fiber is to input light and the secondary reference fiber does this and gives additional benefit of low loss for good reliability.
On page 13-15 the Applicant argues “in this Response, independent claim 1 is amended. In particular, independent claim 1, as amended, presently recites "an avalanche photodiode having an active area, wherein the avalanche photodiode is to maintain a spot, within the active area of the avalanche photodiode, with a width of approximately -40 to -60db at an anode ring level." Support for these features may be found at least at paragraphs [0014] and [0034] of the specification. Kurata and Himeno do not appear to teach or suggest these newly-amended features”.
The Examiner responds that the current amended rejection teaches these amended limitations to be obvious and the Examiner notes that “tailing” and the light output from a fiber is known in the prior art, see the cited references and there is absolutely nothing novel by simply using words like “tailing” and “-60db” to describe what any person of ordinary skill in the art already knows and there is no way that the Examiner can give an allowance just because the Applicant describes what is already known as “tailing” and “-60db”.
On page 14-16 the Applicant argues the same arguments above with respect to the dependent claims and the Examiner response is the same as above.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SITARAMARAO S YECHURI whose telephone number is (571)272-8764. The examiner can normally be reached M-F 8:00-4:30 PM.
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/SITARAMARAO S YECHURI/ Primary Examiner, Art Unit 2893
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