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 .
DETAILED OFFICE ACTION
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 2024-05-29 and 2025-05-15 in compliance with the provisions of 37 CFR 1.97 has been considered by the examiner and made of record in the application file.
Claim Status
Claims 1-26 are pending in this Office Action. No claims have been allowed.
Claim Rejections – 35 U.S.C. § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for the 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.
As reiterated by the Supreme Court in KSR, and as set forth in MPEP 2141 (R-01.2024), II, the factual inquiries of Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), applied for establishing a background for determining obviousness under 35 U.S.C. §103, are summarized as follows:
Determining the scope and content of the prior art;
Ascertaining the differences between the prior art and the claims at issue;
Resolving the level of ordinary skill in the pertinent art; and
Considering objective evidence indicative of obviousness or non-obviousness, if present.
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 C.F.R. § 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 1,2,3,6,7,13,14,15,18,19, 24,25 and 26 are rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. (GB2469625A) in view of Peters et al. (US20030235415A1) and further in view of Huh et al. (US20140301736A1)
Claim 1
O’Gorman teaches a system for optical signal generation in the form of an optical pulse amplitude modulation (PAM) system for transmitting data in a multi-level light signal.
"An optical pulse amplitude modulation system for transmitting data in a multi-level light signal”.
O’Gorman further teaches an array of light sources by disclosing a plurality of light sources, each light source providing an output. "a plurality of light sources, each light source providing an output".
In an analogous art, O’Gorman teaches an optical coupling mechanism and coupling/combining plural optical outputs into a single optical signal by disclosing a coupler for coupling the light source outputs together to provide a combined multi-level light signal. "a coupler for coupling the light source outputs together to provide the combined multi-level light signal".
O’Gorman further, teaches individually configuring each light source in a HIGH or LOW state by disclosing each light source is switchable between at least two states and the system modulates the multi-level light signal by selectively switching the states of the individual light sources. "Being switchable between at least two states ... selectively switching the states of the individual light sources" and O’Gorman teaches that the resulting combined multi-level signal is representative of the received input (data) because O’Gorman transmits data in the multi-level light signal and modulates that signal by selective switching of individual light sources. “1. An optical pulse amplitude modulation system for transmitting data in a multi-level light signal, the system comprising: a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi-level light signal by selectively switching the states of the individual light sources………(57) An optical pulse amplitude modulation (PAM) system 70, for transmitting data in a multi-level light signal, comprises a plurality of light sources 66, 67, 68, e.g. light emitting diodes (LEDS), resonant cavity LEDs or vertical cavity surface emitting lasers (VCSEL), and a coupler 82, e.g. lens or mirror system, for combining the light source outputs together to provide the multi-level light signal. The multi-level light signal is modulated by selectively switching the states of the individual light sources 66, 67, 68. The multi-level light signal may be transmitted into a waveguide or optic fibre 78. The system may be used to transmit multiple bits per symbol at a lower data rate to achieve higher data rates with reduced complexity over polymer optical fibre (POF). [O’Gorman, Claim 1; Abstract].
O’Gorman does not expressly teach a controller/control circuit providing control signals However, in an analogous art, Peters teaches an array of light sources and a control circuit by disclosing a plurality of light sources configured in an array and a controller that provides a plurality of control signals to control respective ones of the light sources. "a plurality of light sources configured in an array ... a controller ... provide a plurality of control signals"
Peters further teaches that the controller controls respective light sources to individually communicate information using multiple distinct levels, such that the per-source control signals are derived from (and correspond to) the information being communicated (i.e., the received input signal). “Optical communication devices and optical communication methods are described. The devices and methods may be implemented in parallel optical communication applications according to some exemplary described aspects to provide enhanced bandwidth. According to one aspect, an exemplary optical communication device includes a plurality of light sources configured in an array and individually adapted to communicate information with respect to an optical communication medium. Individual ones of the light sources are configured to emit light having at least three different and distinct levels to communicate the information with respect to the optical communication medium. The device of this aspect further includes a controller configured to provide a plurality of control signals to control respective ones of the light sources to individually communicate respective information using the at least three different and distinct levels to implement multi-level coding. Other aspects are described………... [0025] According to aspects of the present invention, source optical communication device 12 and individual light sources 24 are configured to implement multi-level coding to communicate information received from one or more external data source. Multi-level coding schemes provide a log in) enhancement to information bandwidth of channels 15 where n is the number of levels used in the coding scheme. As described in further detail below, individual light sources 24, responsive to control from controller 22, emit light having at least three different and distinct levels to communicate the received data with respect to optical communication media 16 and to implement multi-level coding. Light sources 24 are configured to emit optical signals 14 having at least three different and distinct levels in an exemplary embodiment. Additional different and distinct levels may also be provided if additional bandwidth is desired.” [Peters, Abstract; ¶ [0025]].
Huh further evidences multi-level combining by disclosing N directly-modulated lasers generating 2-level optical signals and an optical power combiner combining the N 2-level optical signals to generate a multi-level optical signal. "an optical power combiner ... combine N number of 2-level optical signals ... to generate a 2N-level optical signal" “A directly modulated multi-level optical signal generator and a method thereof are provided. The multi-level optical signal generator includes N number of direct modulation lasers (DMLs) configured to directly modulate source light into a 2-level optical signal, and an optical power combiner configured to combine N number of 2-level optical signals directly modulated by the respective DMLs to generate a 2N-level optical signal………[0008] In one general aspect, a multi-level optical signal generator includes: N number of direct modulation lasers (DMLs) configured to directly modulate source light into a 2-level optical signal; and an optical power combiner configured to combine N number of 2-level optical signals directly modulated by the respective DMLs to generate a 2N-level optical signal.” [Huh, Abstract; ¶ [0008]].
With respect to claim 1, all claim limitations are taught by O’Gorman except for the explicit recitation of a control circuit providing per-source control signals for individually configuring the light sources. However, Peters teaches such a controller and control signals for controlling respective ones of the array of light sources, thereby supplying the claimed control circuit for implementing O’Gorman’s selective switching of individual light source states. [Peters, Abstract; O’Gorman, Claim 1].
It would have been obvious to a person of ordinary skill in the art to incorporate Peters’ controller/control-signal approach into O’Gorman’s multi-level optical system because O’Gorman requires selective per-source switching to modulate a combined multi-level signal that transmits data, and Peters provides a known, predictable way to generate and apply per-source control signals, yielding the predictable result of a combined multi-amplitude optical output representative of the received input data.
Claim 2
With respect to claim 2, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the multi-level output signal is expressly recited as a PAM-equivalent signal.
However, within analogous art, O'Gorman teaches an ‘optical pulse amplitude modulation (PAM) system’ transmitting data in a multi-level light signal. “……...Optical pulse amplitude modulation (PAM) system………...for transmitting data in a multi-level light signal, comprises a plurality of light sources………… light emitting diodes (LEDS), resonant cavity LEDs or
vertical cavity surface emitting lasers (VCSEL), and a coupler ……... lens or mirror system, for combining the light source outputs together to provide the multi-level light signal. The multi-level light signal is modulated……………. The multi-level light signal may be transmitted into a waveguide or optic fibre………... The system may be used to transmit multiple bits per symbol at a lower data rate to achieve higher data rates with reduced complexity over polymer optical fibre (POF)” [O'Gorman, Abstract].
It would have been obvious to implement the multi-level signal of claim 1 as PAM because PAM is a known technique for encoding multiple bits per symbol in multi-level optical transmitters and yields a predictable increase in spectral efficiency.
Claim 3
With respect to claim 3, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the array of light sources is specified to comprise VCSELs.
However, within analogous art, O'Gorman identifies the plurality of light sources as including ‘vertical cavity surface emitting lasers (VCSEL)’.” ………. vertical cavity surface emitting lasers (VCSEL), and a coupler ……... lens or mirror system, for combining the light source outputs together to provide the multi-level light signal. The multi-level light signal is modulated……………. The multi-level light signal may be transmitted into a waveguide or optic fibre………... The system may be used to transmit multiple bits per symbol at a lower data rate to achieve higher data rates with reduced complexity over polymer optical fibre (POF)” [O'Gorman, Abstract].
It would have been obvious to select VCSELs as the array light sources because VCSEL arrays were a known compact, manufacturable light-source technology suitable for multi-level optical transmitters.
Claim 6
With respect to claim 6, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the array of light sources is specified to comprise light emitting diodes (LEDs).
However, within analogous art, O'Gorman teaches that the plurality of light sources may be ‘light emitting diodes (LEDS)’ for generating a multi-level light signal. “ An optical pulse amplitude modulation system for transmitting data in a multi-level light signal, the system comprising: a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi-level light signal by selectively switching the states of the individual light sources………” [O’Gorman, Abstract].
It would have been obvious to use LEDs as the array light sources because O'Gorman expressly identifies LEDs as suitable modulated light sources for PAM multi-level signaling, and this substitution would predictably generate the claimed multi-amplitude output.
Claim 7
With respect to claim 7, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the optical coupling mechanism comprises one or more lenses.
However, within analogous art, O'Gorman teaches a coupler ‘e.g. lens or mirror system’ for combining outputs of modulated light sources into the multi-level light signal.
……………………… a multi-level light signal, the system comprising: a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi-level light signal by selectively switching the states of the individual light sources…………... [O'Gorman, Abstract]
It would have been obvious to employ lenses in the coupling mechanism because lenses are conventional optical elements for coupling/combining light and are explicitly suggested by O'Gorman for the same purpose in multi-level optical signaling.
Claim 13
O’Gorman teaches a multi-level optical signal generation system comprising a plurality of light sources, each providing an output and being switchable between at least two states (HIGH/LOW), and a coupler for coupling the light source outputs together to provide a combined multi-level light signal, where the system modulates the multi-level signal by selectively switching the states of the individual light sources. “An optical pulse amplitude modulation system for transmitting data in a multi level light signal, the system comprising: a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi level light signal by selectively switching the states of the individual light sources.” [O’Gorman, Claim 1].
O’Gorman does not expressly teach a control circuit by disclosing a controller configured However, in an analogous art, Peters teaches a control circuit by disclosing a controller configured to provide a plurality of control signals to control respective ones of a plurality of light sources configured in an array to communicate information.
“Optical communication devices and optical communication methods are described. The devices and methods may be implemented in parallel optical communication applications according to some exemplary described aspects to provide enhanced bandwidth. According to one aspect, an exemplary optical communication device includes a plurality of light
sources configured in an array and individually adapted to communicate information with respect to an optical communication medium. Individual ones of the light sources are configured to emit light having at least three different and distinct levels to communicate the information with respect to the optical communication medium. The device of this aspect further includes a controller configured to provide a plurality of control signals to control respective ones of the light sources to individually communicate respective information using the at least three different and distinct levels to implement multi-level coding. Other aspects are described.” [Peters, p.1, Abstract].
In an analogous art, Huh further teaches generating a multi-level (multi-amplitude) optical signal by combining N 2-level optical signals (from N directly modulated lasers) using an optical power combiner to produce a 2N-level optical signal representative of an input signal. [
“[0008] In one general aspect, a multi-level optical signal generator includes: N number of direct modulation lasers (DMLs) configured to directly modulate source light into a 2-level optical signal; and an optical power combiner configured to combine N number of 2-level optical signals directly modulated by the respective DMLs to generate a 2N-level optical signal. [Huh, ¶ [0008]].
Accordingly, O’Gorman teaches the claimed operations of configuring each light source HIGH/LOW based on input data to generate plural optical output signals, and coupling/combining the plural optical outputs into a single optical signal thereby generating a multi-amplitude output representative of the input.
It would have been obvious to a person of ordinary skill in the art to implement O’Gorman’s per-source selective switching using Peters’ controller/control-signal technique, as reinforced by Huh’s multi-level combining, to obtain the predictable result of a multi-amplitude optical output representative of the received input signal.
Claim 14
With respect to claim 14, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the multi-level output signal comprises a Pulse Amplitude Modulated (PAM) equivalent signal.
However, O’Gorman expressly teaches an “optical pulse amplitude modulation (PAM) system… for transmitting data in a multi-level light signal,” where the multi-level light signal is produced by combining outputs of multiple light sources and modulated by selectively switching the individual source states. “An optical pulse amplitude modulation (PAM) system… for transmitting data in a multi-level light signal… combining the light source outputs…” [O’Gorman, Abstract].
It would have been obvious to implement the multi-amplitude output of claim 13 as a PAM-equivalent signal because PAM is a well-known predictable modulation format for multi-level amplitude signaling to transmit data.
Claim 15
With respect to claim 15, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the array of light sources comprises vertical cavity surface emitting lasers (VCSELs).
However, O’Gorman teaches that the plurality of light sources may be VCSELs.
“a plurality of light sources… e.g. … vertical cavity surface emitting lasers (VCSEL)” [O’Gorman, Abstract].
It would have been obvious to implement the light-source array using VCSELs because VCSELs were known suitable arrayable emitters providing predictable compact optical transmission performance.
Claim 18
With respect to claim 18, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the array of light sources comprises light emitting diodes.
However, O’Gorman expressly identifies LEDs as suitable light sources in the plurality. “a plurality of light sources… e.g. light emitting diodes (LEDS)” [O’Gorman, Abstract].
It would have been obvious to implement the light sources as LEDs because LEDs are known alternative emitters for multi-level optical transmission where multiple emitters are individually switchable and combinable.
Claim 19
With respect to claim 19, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the optical coupling mechanism comprises one or more lenses.
However, O’Gorman teaches the coupler may be a “lens or mirror system” for combining the light source outputs together to provide the multi-level light signal. “a coupler… e.g. lens or mirror system, for combining the light source outputs together to provide the multi-level light signal.” [O’Gorman, Abstract].
It would have been obvious to implement the coupling mechanism using one or more lenses because lens-based optical combining is a conventional predictable technique for coupling and combining outputs from multiple sources into a combined signal.
Claim 24
With respect to claim 24, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein a subset of the array of light sources provides redundancy for other light sources. However, Peters teaches redundancy operations using multiple light emission elements such that if one element fails, communications continue using the remaining elements. “[0042] Additional aspects of the present invention provide redundancy operations which can be implemented using standard binary communications or multi-level coding schemes described herein. For example, light emission elements 30 of a light source 24 could be utilized in a binary communication scheme wherein all of the elements 30 are controlled to be provided in either an on or off emission state to implement redundant communications (i.e., if one element 30 fails, communications can continue to occur using the remaining elements 30)” [Peters, ¶[0042]].
It would have been obvious to include redundant emitters because redundancy in source arrays is a known predictable technique to improve reliability of optical communication systems without changing the fundamental modulation/combining operation.
Claim 25
O’Gorman teaches generating multi-level/multi-amplitude optical signals using multiple light sources by switching source states and combining outputs. “An optical pulse amplitude modulation system for transmitting data in a multi-level light signal, the system comprising:
a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi-level light signal by selectively switching the states of the individual light sources…………….”, [O’Gorman, Claim 1].
O’Gorman does not expressly teach a controller/control circuit providing control signals However, in an analogous art, Peters teaches an array of light sources and a control circuit (controller) configured to provide control signals to control respective ones of the light sources, including multi-level coding with at least three distinct levels. “…. The devices and methods may be implemented in parallel optical communication applications according to some exemplary described aspects to provide enhanced bandwidth. According to one aspect, an exemplary optical communication device includes a plurality of light sources configured in an array and individually adapted to communicate information with respect to an optical communication medium. Individual ones of the light sources are configured to emit light having at least three different and distinct levels to communicate the information with respect to the optical communication medium………...” [Peters, Abstract].
However, in an analogous art, Huh further evidences generating higher-level (2N-level) amplitude outputs by combining multiple 2-level optical outputs, supporting the concept that each source’s HIGH contribution can be selected to differ across sources to realize multi-amplitude outputs. “ a multi-level optical signal generator includes: N number of direct modulation lasers (DMLs) configured to directly modulate source light into a 2-level optical signal; and an optical power combiner configured to combine N number of 2-level optical signals directly modulated by the respective DMLs to generate a 2N-level
optical signal.”,[Huh, ¶[0008]].
With respect to claim 25, all limitations are taught by O’Gorman, Peters, and Huh except wherein the HIGH state is different for each of the light sources. However, Peters expressly teaches multi-level coding with at least three distinct levels across controlled light sources, and O’Gorman/Huh teach constructing multi-level amplitude outputs from multiple sources, which would have motivated selecting differing HIGH output magnitudes per source to realize a desired multi-amplitude level set.
It would have been obvious to a person of ordinary skill in the art to configure different HIGH output levels for different sources because doing so is a predictable design choice to produce a desired set of multi-amplitude levels from multiple controlled sources, enabling higher-order amplitude modulation.
Claim 26
Claim 26 recites a method of optical signal generation in a system with an array of light sources and a control circuit, configuring each light source HIGH/LOW based on a received input to generate a multi-amplitude optical signal, wherein the HIGH state is different for each light source.
O’Gorman teaches generating multi-level optical signals by selective switching of individual light sources and combining outputs. “……. the system comprising: a plurality of light sources, each light source providing an output and being switchable between at least two states; a coupler for coupling the light source outputs together to provide the combined multi-level light signal, wherein the system is configured to modulate the multi-level light signal by selectively switching the states of the individual light sources…………….”, [O’Gorman, Claim 1].
O’Gorman does not expressly teach using a controller to provide control signals to control respective ones of an array of light However, in an analogous art, Peters teaches using a controller to provide control signals to control respective ones of an array of light sources to communicate information using multiple distinct levels. “…………… optical communication device includes a plurality of light sources configured in an array and individually adapted to communicate information with respect to an optical communication medium. Individual ones of the light sources are configured to emit light having at least three different and distinct levels to communicate the information with respect to the optical communication medium. The device of this aspect further includes a controller configured to provide a plurality of control signals to control respective ones of the light sources to individually communicate respective information using the at least three different and distinct levels to implement multi-level coding………”, [Peters, Abstract].
However, in an analogous art, Huh further teaches generating a 2N-level optical signal by combining N 2-level optical signals, evidencing multi-amplitude generation using plural binary-controlled sources. “N number of direct modulation lasers (DMLs) configured to directly modulate source light into a 2-level optical signal; and an optical power combiner configured to combine N number of 2-level optical signals directly modulated by the respective DMLs to generate a 2N-level optical signal.”, [Huh, ¶[0008]].
With respect to claim 26, all limitations are taught by O’Gorman, Peters, and Huh except wherein the HIGH state is different for each of the light sources. However, for the same reasons as claim 25 (multi-level coding and multi-level combining), it would have been obvious to assign different HIGH output magnitudes across the sources to obtain predictable multi-amplitude signaling.
It would have been obvious to a person of ordinary skill in the art to perform the recited method using different HIGH-state levels per source because such weighting is a known predictable technique for implementing multi-amplitude modulation with multiple controlled emitters.
Claims 4,5,16 and 17 are rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al. and Su et al. (US 9,620,934)
Claim 4
With respect to claim 4, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the individual HIGH states are binary weighted and the optical output area is scaled by a factor of two.
However, within analogous art, Peters teaches an array of light sources [0042] Additional aspects of the present invention provide redundancy operations which can be implemented using standard binary communications or multi-level coding schemes described herein. For example, light emission elements 30 of a light source 24 could be utilized in a binary communication scheme wherein all of the elements 30 are controlled to be provided in either an on or off emission state to implement redundant communications (i.e., if one element 30 fails, communications can continue to occur using the remaining elements 30). [Peters (US 2003/0235415 A1), p.7, ¶ [0042]].
Peters does not expressly teach combining optical signals with optical intensities However, in an analogous art, Huh teaches combining optical signals with optical intensities at a 2:1 ratio to generate PAM-4, “[0033] Optical signals, into which electrical 2-level signals are directly modulated by the two DMLs 10-1 and 10-2, are combined by the 2:1 optical power combiner 12, and thus, a PAM-4-level optical signal is generated. To provide a theoretical
analysis on this, an optical signal modulated by the DML #1 10-1 may be expressed as Equation (1) ……………..., and an optical signal modulated by the DML #2 10-2 may be expressed as Equation (2) ………. where E denotes an electric field, A denotes data, w denotes a wavelength of laser, and <ⴔ> denotes a phase.” [Huh, ¶ [0033]].
Huh does not expressly teach semiconductor lasers with apertures However, in an analogous art, Su teaches semiconductor lasers with apertures (optical output areas), enabling selection/design of differing output areas. each light source has an optical output area that differs by a factor of two relative to another light source (via differing apertures/output areas)
“The invention relates to semiconductor lasers, and more particularly, to a flip-chip assembly comprising an array of vertical cavity surface emitting lasers (VCSELs)……. In optical communications networks, optical transceiver and transmitter modules are used to transmit optical signals over optical fibers. The optical transceiver or transmitter module includes a laser that generates amplitude modulated optical signals that represent data, which are then transmitted over an optical fiber coupled to the transceiver or transmitter module. Various types of semiconductor lasers are typically used for this purpose, including, for example,
VCSELs and edge emitting lasers, which may be further divided into subtypes that include Fabry Perot (FP) and Distributed Feedback (DFB) lasers. Some optical transmitter or transceiver modules have only a single transmit channel comprising a single laser, which is sometimes referred to as a singlet. Other optical transmitter or transceiver modules have multiple transmit channels comprising multiple lasers. The multi-channel optical transmitter or transceiver module is commonly referred to as a parallel optical transmitter or transceiver module. There is an ever-increasing demand for optical transmitter or transceiver modules that have increasingly larger numbers of transmit channels. Of course, increasing the number of transmit channels allows the bandwidth capacity of an optical communications network to be increased. In order to meet this demand, it is known to fabricate an array of lasers on a single semiconductor substrate of the electrical subassembly (ESA) of the module. For example, it is known to fabricate a one-dimensional or two-dimensional array of VCSELs on a single semiconductor substrate. Fabricating the VCSELs on a single semiconductor substrate allows the spacing, or pitch, between adjacent VCSELs to be decreased, which, in turn, allows the number of VCSELs that can be integrated on a single semiconductor substrate to be increased. However, the manufacturing yield for this type of semiconductor device is relatively low due to the fact that the semiconductor device is deemed defective and is discarded if even one of the VCSELs of the array is found to be defective. The relatively low manufacturing yield of this type of semiconductor device increases the overall costs of the semiconductor devices. Because semiconductor devices that have fewer numbers of VCSELs on them can be manufactured with higher yield, and thus at reduced costs, it is known to construct an array of VCSELs by creating an array of multiple semiconductor devices that have either only a singlet VCSEL or a few VCSELs on them. This approach presents other difficulties, however, one of which is the difficulty associated with precisely aligning the VCSELs with their respective optical coupling elements. Consequently, to date, using multiple semiconductor devices having only either a singlet VCSEL or a very small number of VCSELs on them to create a larger array of VCSELs is not a viable solution. Accordingly, a need exists for an assembly having multiple semiconductor devices with only either a singlet or a very small number of VCSELs on them that can be combined to create a precisely-aligned larger array of VCSELs.” [Su, Technical and background of the invention]
It would have been obvious to apply Huh’s 2:1 optical weighting to the multi-level light-source set of Peters/O'Gorman and to implement the weighting by selecting different emitting apertures/output areas (as taught by So), because this is a predictable way to realize binary weighted optical amplitudes.
Claim 5
With respect to claim 5, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein the array of light sources is specified to comprise edge-emitting lasers.
However, within analogous art, Su teaches that optical transmitter modules may use ‘VCSELs and edge emitting lasers’ including FP and DFB subtypes. “………………. semiconductor lasers, and more particularly, to a flip-chip assembly comprising an array of vertical cavity surface emitting lasers (VCSELs)…………………………..., VCSELs and edge emitting lasers, which may be further divided into subtypes that include Fabry Perot (FP) and Distributed Feedback (DFB) lasers. Some optical transmitter or transceiver modules have only a single transmit channel comprising a single laser………………. For example, it is known to fabricate a one-dimensional or two-dimensional array of VCSELs on a single semiconductor substrate. Fabricating the VCSELs on a single semiconductor substrate allows the spacing, or pitch, between adjacent VCSELs to be decreased, which, in turn, allows the number of VCSELs ………………………. if even one of the VCSELs of the array is found to be defective. The relatively low manufacturing yield ……………………..., and thus at reduced costs, it is known to construct an array of VCSELs by creating an array of multiple semiconductor devices that have either only a singlet VCSEL or a few VCSELs on them. This approach presents other difficulties, however, one of which is the difficulty associated with precisely aligning the VCSELs with their respective optical coupling elements. Consequently, to date, using multiple semiconductor devices having only either a singlet VCSEL or a very small number of VCSELs on them to create a larger array of VCSELs is not a viable solution. …………….. a very small number of VCSELs on them that can be combined to create a precisely-aligned larger array of VCSELs.” [Su, Technical and background of the invention]
It would have been obvious to implement the light-source array with edge-emitting lasers because edge-emitting lasers were known alternatives to VCSELs for optical transmitters, and substitution of one known laser type for another yield’s predictable operation.
Claim 16
With respect to claim 16, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the light source HIGH state of each light source in the array of light sources is binary weighted with respect to another light source of the array of light sources, with an optical output area of each being a factor of two with respect to another light source of the array of light sources However, O’Gorman teaches that for higher PAM applications multiple optical devices may be used and devices may have different power states (e.g., low/medium/high), supporting selection of distinct output strengths among sources.
“The present application overcomes the complexity of the prior art multi level optical modulation systems by coupling the outputs from multiple light sources together. By adjusting the number of light sources switched on or off, the level of the combined output may be adjusted. Thus for example, for a PAM-4 coding system where 4 distinct optical levels are transmitted per symbol, the optical output may be created from 3 optical sources, examples of suitable sources would include Light Emitting Diodes (LED), Resonant Cavity Light Emitting Diodes (RCLED) or Vertical Cavity Surface Emitting Lasers (VCSEL). Each of the 3 optical sources is modulated independently between two states to create the required multi-level optical output. PAM-4 coding associates one of 4 possible levels with the transmitted output during each symbol period, represented as -3, -1, +1, +3. The -3 level corresponds to a situation where the 3 optical devices are in an 'off' state (which may be no output or a low power light output). The -1 level corresponds to having one optical source in an 'on' state, i.e. a high power light output. The 2nd level +1 corresponds to having two optical sources operating in an 'on' state and the 3rd level +3 corresponds to having all three optical sources
switched to an 'on' state. It will be appreciated that the optical sources are not limited to having just two states and thus for example, for higher PAM applications multiple optical devices having more than two states might be employed, for example each optical device might have an "off" or low power state, a medium (half) power state and 'on' high power . Whilst use of more than two states will have some the problems identified with the prior art, the use of multiple optical devices will significantly mitigate these in comparison to the use of a single multi level optical device attempting to achieve the same number of levels as 5 the multiple optical devices. [O’Gorman, Detailed Description].
In an analogous art, Huh further teaches combining N binary (2-level) optical signals to produce a 2N-level signal, evidencing that multi-level amplitude generation can be achieved by assigning differing contributions across plural binary-controlled sources “optical intensity weighting (2:1) for PAM-4 generation “Combine N number of 2-level optical signals… to generate a 2N-level optical signal.”, “[0033] Optical signals, into which electrical 2-level signals are directly modulated by the two DMLs 10-1 and 10-2, are combined by the 2:1 optical power combiner 12, and thus, a PAM-4-level optical signal is generated. To provide a theoretical
analysis on this, an optical signal modulated by the DML #1 10-1 may be expressed as Equation (1) ……………..., and an optical signal modulated by the DML #2 10-2 may be expressed as Equation (2) ………. where E denotes an electric field, A denotes data, w denotes a wavelength of laser, and <ⴔ> denotes a phase.” [Huh, ¶ [0033]].
Huh does not expressly teach semiconductor lasers with apertures However, in an analogous art, Su teaches semiconductor lasers with apertures, enabling selection/design of differing optical output areas.” scaled optical output areas/apertures enabling differing optical output areas”, “The invention relates to semiconductor lasers, and more particularly, to a flip-chip assembly comprising an array of vertical cavity surface emitting lasers (VCSELs)……. In optical communications networks, optical transceiver and transmitter modules are used to transmit optical signals over optical fibers. The optical transceiver or transmitter module includes a laser that generates amplitude modulated optical signals that represent data, which are then transmitted over an optical fiber coupled to the transceiver or transmitter module. Various types of semiconductor lasers are typically used for this purpose, including, for example,
VCSELs and edge emitting lasers, which may be further divided into subtypes that include Fabry Perot (FP) and Distributed Feedback (DFB) lasers. Some optical transmitter or transceiver modules have only a single transmit channel comprising a single laser, which is sometimes referred to as a singlet. Other optical transmitter or transceiver modules have multiple transmit channels comprising multiple lasers. The multi-channel optical transmitter or transceiver module is commonly referred to as a parallel optical transmitter or transceiver module. There is an ever-increasing demand for optical transmitter or transceiver modules that have increasingly larger numbers of transmit channels. Of course, increasing the number of transmit channels allows the bandwidth capacity of an optical communications network to be increased. In order to meet this demand, it is known to fabricate an array of lasers on a single semiconductor substrate of the electrical subassembly (ESA) of the module. For example, it is known to fabricate a one-dimensional or two-dimensional array of VCSELs on a single semiconductor substrate. Fabricating the VCSELs on a single semiconductor substrate allows the spacing, or pitch, between adjacent VCSELs to be decreased, which, in turn, allows the number of VCSELs that can be integrated on a single semiconductor substrate to be increased. However, the manufacturing yield for this type of semiconductor device is relatively low due to the fact that the semiconductor device is deemed defective and is discarded if even one of the VCSELs of the array is found to be defective. The relatively low manufacturing yield of this type of semiconductor device increases the overall costs of the semiconductor devices. Because semiconductor devices that have fewer numbers of VCSELs on them can be manufactured with higher yield, and thus at reduced costs, it is known to construct an array of VCSELs by creating an array of multiple semiconductor devices that have either only a singlet VCSEL or a few VCSELs on them. This approach presents other difficulties, however, one of which is the difficulty associated with precisely aligning the VCSELs with their respective optical coupling elements. Consequently, to date, using multiple semiconductor devices having only either a singlet VCSEL or a very small number of VCSELs on them to create a larger array of VCSELs is not a viable solution. Accordingly, a need exists for an assembly having multiple semiconductor devices with only either a singlet or a very small number of VCSELs on them that can be combined to create a precisely-aligned larger array of VCSELs.” [Su, Technical and background of the invention]
It would have been obvious to implement binary weighting (e.g., factor-of-two area/output scaling) across the sources because it is a known predictable design technique to realize evenly spaced multi-bit amplitude levels using multiple on/off emitters.
Claim 17
With respect to claim 17, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the array of light sources comprises edge-emitting lasers.
However, O’Gorman teaches the use of multiple optical devices (including laser sources) to generate multi-level amplitude outputs; edge-emitting semiconductor lasers were known interchangeable laser sources for such multi-device transmitters. “The present application overcomes the complexity of the prior art multi-level optical modulation systems by coupling the outputs from multiple light sources together. By adjusting the number of light sources switched on or off, the level of the combined output may be adjusted. Thus, for example, for a PAM-4 coding system where 4 distinct optical levels are transmitted per symbol, the optical output may be created from 3 optical sources, examples of suitable sources would include Light Emitting Diodes (LED), Resonant Cavity Light Emitting Diodes (RCLED) or Vertical Cavity Surface 10 Emitting Lasers (VCSEL). Each of the 3 optical sources is modulated independently between two states to create the required multi-level optical output……………” [O’Gorman, Detailed Description].
However, in an analogous art Su, teaches optical transmitter modules using edge-emitting lasers as semiconductor lasers. “The array comprises edge-emitting lasers” “In optical communications networks, optical transceiver and transmitter modules are used to transmit optical signals over optical fibers. The optical transceiver or transmitter module includes a laser that generates amplitude modulated optical signals that represent data, which are then transmitted over an optical fiber coupled to the transceiver or transmitter module. Various types of semiconductor lasers are typically used for this purpose, including, for example, VCSELs and edge emitting lasers, which may be further divided into subtypes that include Fabry Perot (FP) and Distributed Feedback (DFB) lasers………...” [Su, Background of the invention].
It would have been obvious to substitute edge-emitting lasers for other laser sources in the array because they are known alternative emitters for optical transmission under electronic control, yielding predictable optical output signals.
Claim 8 is rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al. and Caer et al. (US 10,243,323 B2).
Claim 8
With respect to claim 8, all limitations of claim 1 are taught by O'Gorman, Peters and Huh
except wherein the optical coupling mechanism is specifically recited as a photonic integrated circuit (PIC).
However, within analogous art, Caer teaches a silicon photonic chip (PIC) including an optical waveguide on a substrate and optical elements configured to couple/deflect emitted light into the waveguide “the optical coupling mechanism comprises a photonic integrated circuit (PIC)”. “Embodiments include a silicon photonic chip having a substrate, an optical waveguide on a surface of the substrate and a cavity. The cavity includes an electro-optical component, configured for emitting light perpendicular to said surface and a lens element arranged on top of the electrooptical component. The lens is configured for collimating light emitted by the electro-optical component. The chip also includes a deflector arranged on top of the lens element and configured for deflecting light collimated through the latter toward the optical waveguide. The lens element includes electrical conductors connected to the electro-optical component. The electrical conductors of the lens element may for instance include one or more through vias, one or more bottom electrical lines on a bottom side of the lens element (facing the electro-optical component), and at least one top electrical line.” [Caer, Abstract]
It would have been obvious to implement O'Gorman’s optical coupling/combining using a PIC as taught by Caer because PICs provide a compact, integrated, and predictable platform for routing and combining optical signals using waveguides.
Claim 9 is rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al. and Caer et al. and Harris (US 2021/0336414 A1)
Claim 9
With respect to claim 9, all limitations of claims 8 are taught by O'Gorman, Peters, Huh, and Caer except wherein the PIC is specified to comprise a waveguide coupler.
However, within analogous art, Harris teaches waveguide coupling structures such as ‘a directional coupler or a Y-junction’ in photonic integrated circuits. “the PIC comprises a waveguide coupler”, “[0110] An example of such an optical adder is depicted in FIG. 3A, in accordance with some embodiments (in FIGS. 3A-3C, broken lines represent optical channels, such as optical waveguides, and solid lines represent electrical channels, such as conductive traces). This optical adder is embedded in an interferometer having a pair of optical waveguides. An optical beam splitter 31 receives input light and splits the received light (e.g., in equal parts) between the waveguides of the interferometer. The optical beam splitter may be implemented using any suitable optical device, including for example a directional coupler or a Y-junction. A series of optical phase shifters 32 is embedded in one of the waveguides. Each phase shifter is controlled by a respective control voltage V1 , V2 , V3 and V4 (though not all embodiments are limited to having four phase shifters, as any suitable number of phase shifters greater than one may be used). Optical phase shifters can be actuated by any mechanism including, but not limited to, voltage, current, heat, a different wavelength of light, or mechanical means. One example of an optical phase shifter is described below in connection FIG. 3D. Each phase shifter modulates the phase of the optical signal present on the lower waveguide by an amount that depends on the applied voltage. Let f(V,) be the amount by which a phase shifter modulates the phase of the optical signal……….”
[Harris, ¶ [0110]].
It would have been obvious to include a waveguide coupler in the PIC because waveguide couplers are standard PIC building blocks for combining/splitting optical power, yielding predictable combining in the claimed system.
Claim 10 is rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al. and Caer et al. and Lu et al., “Flip-chip integration of tilted VCSELs onto a silicon photonic integrated circuit (PIC)”.
Claim 10
With respect to claim 10, all limitations of claims 8 are taught by O'Gorman, Peters, Huh, and Caer except wherein the array of light sources is bonded to the PIC.
However, within analogous art, Lu teaches VCSELs that are passively-aligned and flip-chip bonded to a silicon photonic integrated circuit (PIC). “the array of light sources is bonded to the PIC”, “………hybrid laser integration, in which vertical cavity surface emitting lasers (VCSELs) are passively-aligned and flip-chip bonded to a Si photonic integrated circuit (PIC), with a tilt-angle optimized for optical insertion into standard grating-couplers. A tilt-angle of 10° is achieved by controlling the reflow of the solder ball deposition used for the electrical-contacting and mechanical-bonding of the VCSEL to the PIC. After flip-chip integration, the VCSEL-to-PIC insertion loss is −11.8 dB, indicating an excess coupling penalty of −5.9 dB, compared to Fibre-to-PIC coupling. Finite difference time domain simulations indicate that the penalty arises from the relatively poor match between the VCSEL mode and the grating-coupler…………. The last decade has seen the emergence of silicon photonics as a potential platform for lowcost sensing and point-of-care medical applications, based on re-deploying established complementary metal oxide semiconductor (CMOS) technologies, at volume, for photonic applications [1,2]. The high index-contrast in the silicon-on-insulator (SOI) architecture allows for photonic integrated circuits (PICs) with very small footprints, while CMOS lithography, implantation and deposition processes allow for the implementation of a rich catalogue of passive and active components available through multi-project wafer foundry services [3]. The most significant roadblock to realizing fully functional Si-PICs is the lack of an intrinsic light source in silicon. Despite some recent work towards CMOS-compatible Gebased lasers [4], most research has focused on the integration of III-V materials and devices on silicon, to unlock its full photonic potential. One approach is heterogeneous integration, where III-V material is bonded or transfer-printed to the Si-PIC, and then etched to create a cavity condition for on-PIC lasing [5]. Several architectures for heterogenous III-V laser on the Si photonics platform have been successfully demonstrated [6,7], but issues around the process compatibility with a CMOS foundries remain to be resolved, in order to optimize yields and reliability still need to be resolved. An alternative approach is hybrid integration, where stand-alone “known good” laser devices are opto-mechanically coupled to the Si-PIC, using either an edge- or grating coupling scheme. Although it is the simplest approach, hybrid integration by butt-coupling a laser into the edge-coupler of a Si-PIC often has sub-μm alignment tolerances, and requires an optical interposer [8], making volume-packaging a challenge. Hybrid laser integration using a grating-coupler to launch light into the Si-PIC brings more relaxed alignment tolerances…………” [Lu, Abstract/Intro page].
It would have been obvious to bond the light-source array to the PIC because flip-chip bonding provides a known, reliable integration technique that reduces optical alignment complexity and yields a predictable integrated transmitter assembly.
Claims 11, 20 and 21 are rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al., Caer et al. and Mentovich (WO2018002675A1).
Claim 11
With respect to claim 11, all limitations of claims 1 and 8 are taught by O'Gorman, Peters, Huh, and Caer except wherein the light-source array is laterally adjacent to the PIC.
However, within analogous art, Mentovich teaches at least a portion of an optoelectronic transducer positioned adjacent a coupled waveguide assembly “the array of light sources is laterally adjacent to the PIC” “…….least a portion of the optoelectronic transducer is positioned adjacent the coupled waveguide assembly. The coupled waveguide assembly comprises a low-index waveguide, a high-index waveguide proximate the low-index waveguide, and a reflective surface configured to change a pathway of the optical signals to direct the optical signals _5 from the optoelectronic transducer into the low-index waveguide or from the low-index wave_!.!ide into the optoelectronic transducer. In some cases, the high-index waveguide formed within and may be integral to the substrate defining the PIC. In other cases, the high-index-waveguide may be disposed on a surface of the PIC. The PIC may comprise at least one of a 10 nanophotonic silicon on insulator (SOI) substrate or a silicon interposer. Additionally, or alternatively, at least one of the high-index waveguide or the lowindex waveguide may define a tapered section that is configured to change a mode of the optical signal passing therethrough. The high-index waveguide may, in some cases, be •
at least partially_ contained_within _the low-index waveguide to create_tbe_coupled_
15 waveguide assembly. In other cases, the high-index waveguide may be disposed
adjacent to the low-index waveguide. The PIC may be connected to a printed circuit board using at least one of a through-silicon via (TSV) or a redistribution layer (RDL). The optoelectronic transducer may comprise at least one of a vertical-cavity surface-emitting laser (VCSEL) or a photodiodes. In some embodiments, the reflective surface may comprise a first reflective surface configured to change a pathway of the optical signals to direct the optical signals from the optoelectronic transducer into the low-index waveguide or from the low-index waveguide into the optoelectronic transducer, and the coupled waveguide assembly may further comprise a second reflective surface configured to change a pathway of the optical signals to direct the optical signals from the optical fiber into the coupled
waveguide system or from the coupled waveguide system into the optical fiber. In other
embodiments, the reflective surface may comprise a prism separate from and disposed
proximate the low-index waveguide. The reflective surface may comprise an angled facet
of the low-index waveguides. In some cases, the coupled waveguide system may comprise a plurality of at least one of the low-index waveguides or the high-index waveguide.
In other embodiments, a method of assembling an optical coupler is provided that
includes providing a photonic integrated circuit (PIC) comprising a substrate; supporting
an optoelectronic transducer on the PIC, wherein the optoelectronic transducer is
configured to convert between optical signals and corresponding electrical signals; and
forming a coupled waveguide assembly supported by the PIC. The coupled waveguide …….” [Mentovich, BRIEF SUMMARY]
It would have been obvious to place the light-source array laterally adjacent to the PIC because side-by-side adjacency is a known packaging/layout approach to facilitate coupling to waveguides and simplifies integration with predictable optical routing.
Claim 20
With respect to claim 20, all limitations of claim 13 are taught by O’Gorman, Peters, and Huh except wherein the optical coupling mechanism comprises a photonic integrated circuit (PIC).
However, Mentovich teaches photonic integrated circuit structures that include coupling of optical signals via waveguides/couplers in a PIC context. “ An optical coupler and method of assembly are described that provide efficient coupling from the photonic integrated
circuit (PIC) waveguide layer to external components, such as optical fibers, VCSELs, photodetectors, and gain blocks, among others. The optical coupler includes a PIC that can be supported by-a printed circuit board, an optoelectronic transducer supported by the
PIC that can convert between optical signals and corresponding electrical signals, and a coupled waveguide assembly. The coupled waveguide assembly includes a low-index waveguide, a high-index waveguide, and a reflective surface that changes a pathway of the optical signals to direct the optical signals from the optoelectronic transducer into the low index waveguide or from the low-index waveguide into the optoelectronic transducer…………”
[Mentovich, Abstract].
It would have been obvious to implement O’Gorman’s coupling/combining function using a PIC as taught by Mentovich to obtain the predictable result of compact integrated coupling/combining of the plural optical outputs.
Claim 21
With respect to claim 21, all limitations of claim 20 are taught by O’Gorman, Peters, Huh, and Mentovich except wherein the PIC comprises a waveguide coupler.
However, Mentovich teaches coupling from a PIC waveguide layer using an optical coupler (i.e., a waveguide coupler structure). “The couplers and methods described above may thus be applied to plurality of waveguides to provide massive input/output to the PIC. Proper design of the waveguide fan-out a.nd placement of the optical coupling_structure on each_waveguide may thus facilitate coupling directly to a fiber array or to a multi-core fiber, using an individual coupler properly placed to couple an individual core of the fiber. Moreover, the exact angle of reflection can be adjusted by modifying the design of the reflective surface to provide "perfect" vertical coupling or coupling to any custom angle………………. Embodiments of the invention may thus be suitable for PIC assemblies targeting applications in various fields, such as telecommunications, optical interconnects, sensors, etc. Embodiments of the invention may further provide additional features and benefits. For example, the optical coupler can be formed on a PIC or on an interposer, with the latter providing additional electrical functionalities and interconnections such as TSVs as
noted_above. In this regard, an optoelectmnicJransducer (e.g., a VCSEL) may be flip-
chip assembled on top of the out-of-plane optical coupler, and electrical interconnection
from the interposer's bond pads to the VCSEL's electrodes may be facilitated with microbumps (electrically conductive beads). method of assembling an optical coupler, the method comprising: providing a photonic integrated circuit (PIC) comprising a substrate; supporting an optoelectronic transducer on the PIC, wherein the optoelectronic transducer is configured to convert between optical signals and corresponding electrical signals; and forming a coupled waveguide assembly supported by the PIC, wherein the coupled waveguide assembly is configured to direct the optical signals between the optoelectronic transducer and an optical fiber, and wherein at least a portion of the optoelectronic transducer is positioned adjacent the coupled waveguide assembly, wherein the coupled waveguide assembly is formed by coupling at least one lowindex waveguide with at least one high-index waveguide and providing a reflective surface configured to change a pathway of the optical signals to direct the optical signals from the optoelectronic transducer into the low-index waveguide or from the low-index waveguide into the optoelectronic transducer. [Mentovich, Claim 14]
It would have been obvious to use a waveguide coupler within the PIC because waveguide coupling is a conventional predictable PIC mechanism for routing and combining optical signals.
Claim 12 is rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al. and Devine (US 6,821,026 B2).
Claim 12
With respect to claim 12, all limitations of claim 1 are taught by O'Gorman, Peters and Huh except wherein a subset of the light sources provides redundancy for other light sources.
However, within analogous art, Devine teaches a redundant configurable laser array that enables selection of one or more lasers from an array to provide the best aligned/coupled laser signal, i.e., functional redundancy within the array. “a subset of the array of light sources provides redundancy for other light sources of the array.”, “…….FIG. 1 shows a 3x3 array of lasers, i.e., a VCSEL array, such as on a GaAs chip. The VCSEL laser array can be provided on a square grid as shown in FIG. 1, or it could also be provided on a hexagonal grid for higher packing density, or on some other grid geometry. The laser chip may support multiple optical links, only one of which is shown by arrow 19………… FIG. 2 illustrates a first substrate or submount 10 such as a silicon or ceramic substrate, a multi-chip module, a package board, backplane or similar component which is provided with a VCSEL laser array chip 12 and support logic control 20 for the VCSEL laser array chip. The support logic control is typically provided by a CMOS logic chip which feeds a GHz data signal to the laser chip for transmission over an optical fiber 14. The CMOS chip 20 selects the best laser source in the laser array based on a relatively low speed or data rate electrical feedback logic signal 22 from a receiver chip 24 mounted on a substrate or submount 26 such as a silicon or ceramic substrate, a multi-chip module, a package board, backplane or similar component, which also mounts an optical detector 16 thereon FIG. 3 illustrates a bi-directional communication system embodiment of the present invention which uses first and second single interwoven array chips 30 mounted on a first and second substrate 10, 12. Each interwoven array chip 30 has both a laser array having an array of VCSEL lasers 32 interwoven with a detector array of optical sense diodes 34. Each interwoven array chip 30 provides for bi-directional data communications over a single optical fiber 14. Moreover each interwoven array chip also provides the ability to "wrap" an optical signal at the receiver end of the optical communication link and return a signal back to the source laser array chip for use as an optical feedback signal in the source laser selection process. The signals generated directly by the photodiodes can be used at the receiver to select an efficiently coupled photodiode without the use of a feedback loop or signal…………. While several embodiments and variations of the present invention for a redundant configurable VCSEL laser array optical light source are described in detail herein, it should be apparent that the disclosure and teachings of the present invention will suggest many alternative designs to those 20 skilled in the art. Having thus described our invention, what we claim as new and desire to secure by Letters Patent is: 1. Apparatus for providing optical data signals over an optical data link comprising: an array of surface emitting lasers provided in a single semiconductor chip which is mounted on a first substrate; an optical detector mounted on a second substrate; an optical data link connecting optical data signals from at least one laser of the array of lasers to the optical detector mounted on a second substrate; and a selection means for selecting one or more of the lasers in the array of surface emitting lasers for optical coupling to the optical data link based on the best aligned and coupled laser to provide the best laser signal from an array of surface emitting lasers, including logic means for directing a GHz signal to the semiconductor chip for transmission over the optical data link, and also for selecting one or more lasers in the array of surface emitting lasers based on a feedback signal received from a receiver indicating the best aligned and coupled laser of the array of surface emitting lasers.” [Devine, (col.3-4)]
It would have been obvious to include redundancy because optical transmitter arrays were known to benefit from redundant elements to improve yield and reliability, and Devine provides a predictable selection-based redundancy approach for arrays.
Claims 22 and 23 are rejected under 35 U.S.C. §103 as being unpatentable over O’Gorman et al. in view of Peters et al. and further in view of Huh et al., Mentovich and Lu
Claim 22
With respect to claim 22, all limitations of claim 20 are taught by O’Gorman, Peters, Huh, and Mentovich except wherein the array of light sources is bonded to the PIC.
However, Lu teaches flip-chip bonding VCSELs onto a silicon photonic integrated circuit (PIC).
“(VCSELs) are passively-aligned and flip-chip bonded to a Si photonic integrated circuit (PIC), with a tilt-angle optimized for optical insertion into standard grating-couplers. A tilt-angle of 10° is achieved by controlling the reflow of the solder ball deposition used for the electrical-contacting and mechanical-bonding of the VCSEL to the PIC. After flip-chip integration, the VCSEL-to-PIC insertion loss is −11.8 dB, indicating an excess coupling penalty of −5.9 dB, compared to Fibre-to-PIC coupling. Finite difference time domain simulations indicate that the penalty arises from the relatively poor match between the VCSEL mode and the grating-coupler.” [Lu, Abstract].
It would have been obvious to bond the light-source array to the PIC because flip-chip bonding is a known predictable integration technique providing compact packaging and low-loss coupling between sources and PIC waveguides.
Claim 23
With respect to claim 23, all limitations of claim 20 are taught by O’Gorman, Peters, Huh, and Mentovich except wherein the array of light sources is laterally adjacent to the PIC.
However, Mentovich teaches arrangements in which an optoelectronic transducer is positioned adjacent a coupled waveguide assembly of a PIC, consistent with lateral adjacency between a source/transducer and the PIC coupling structure. “ In some cases, the coupled waveguide system may comprise a plurality of at least one of the low-index waveguide or the high-index waveguide. In other embodiments, a method of assembling an optical coupler is provided that includes providing a photonic integrated circuit (PIC) comprising a substrate; supporting
35 an optoelectronic transducer on the PIC, wherein the optoelectronic transducer is
configured to convert between optical signals and corresponding electrical signals; and
forming a coupled waveguide assembly supported by the PIC. The coupled waveguide………..[ Mentovich, Summary]
However, in an analogous art Lu further teaches physical integration/placement of electro-optical components (including VCSELs) on/within a silicon photonic integrated circuit substrate, inherently requiring adjacency between the emitter array and the PIC waveguide region “ .…In our new approach, a tilted-VCSEL is bonded directly to the PIC, without any postprocessing
layers, such that the VCSEL mode is correctly aligned for optical insertion into a
standard grating-coupler [14] - see Fig. 1. The desired tilt-angle (10°) is achieved by
controlling the reflow of the solder ball deposition (SBD) for the electrical-contacting and
mechanical-bonding of the VCSEL to the PIC. Essentially, this approach allows the VCSEL
bond-pads, which are originally designed for wire-bond connections, to be repurposed into a
means of creating a direct VCSEL-PIC electrical connection. This approach is compatible
with existing flip-chip alignment and bonding technologies, and the absence of surface
treatment or post-processing ensures maximum compatibility with bio-sensing applications,
because it leaves functional-layers uncontaminated, and allows them to be brought into close
proximity with on-PIC waveguide and resonator structures [15]. The passive-alignment of the
VCSEL on the PIC is made using alignment markers, allowing for very high-speed assembly
and packaging, leading to a cost-effective method of hybrid-integration of lasers on Si-PICs……….”[Lu, Introduction].
It would have been obvious to position the array laterally adjacent to the PIC because adjacent placement is a conventional predictable layout for coupling sources into PIC waveguides while simplifying packaging and alignment.
It is noted that any citations to specific, pages, columns, lines, or figures in the prior art references and any interpretation of the reference should not be considered to be limiting in any way. A reference is relevant for all it contains and may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art. See MPEP 2123.
Conclusion
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/MOHAMMED ABDELRAHEEM/Examiner, Art Unit 2635
/DAVID C PAYNE/Supervisory Patent Examiner, Art Unit 2635