DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 13th December 2024 has been considered by the examiner.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4, 8-11, 15-16, and 18-19 are rejected under 35 U.S.C. 103 as being unpatentable over Hjartarson (USPUB 20190238234).
As per claims 1 and 15,
Hjartarson teaches an electro-absorption modulated laser (Paragraph [0003] – "Electro-absorption modulators (EAM) are commonly used in the fiber optics world. EAMs are used as external modulators of light output from continuous wave lasers.") comprising:
a first diode (discrete or integrated laser diode) operable to receive a first voltage to generate a first output (FIG. 1, continuous optical input 122; paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC)."); and a second diode (FIG. 1, electro-absorption modulator 120) coupled to the first diode and operable to receive a second voltage (FIG. 1, continuous optical input 122 and electro-absorption modulator 120; Paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC). The optical output 124 may also comprise an SSC for coupling to other optical components. Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120."), wherein the second diode generates a photocurrent using the first output and the second voltage (Paragraph [0018] – "The optical output 124 may also comprise an SSC for coupling to other optical components. Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120. An input modulation signal, i.e. an analog electrical signal, provided at control input 132, and fed through elements of the control circuitry to the control terminal drive transistor 138 of the driver circuitry of the electro-absorption modulator 120 for modulation of the optical output signal").
Hjartarson does not explicitly teach that the second diode generates a photocurrent using the first output and the second voltage, but one of ordinary skill in the art would recognize that the second voltage impacts the absorption of photons passing through the electro-absorption modulator, which then causes the electro-absorption modulator to generate a photocurrent.
As per claim 8, Hjartarson teaches a device comprising: an electro-absorption modulated laser (Paragraph [0003] – "Electro-absorption modulators (EAM) are commonly used in the fiber optics world. EAMs are used as external modulators of light output from continuous wave lasers.") comprising: a first diode (discrete or integrated laser diode) operable to receive a first voltage to generate a first output (FIG. 1, continuous optical input 122; paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC)."); and a second diode (FIG. 1, electro-absorption modulator 120) coupled to the first diode and operable to receive a second voltage (FIG. 1, continuous optical input 122 and electro-absorption modulator 120; Paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC). The optical output 124 may also comprise an SSC for coupling to other optical components. Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120."), wherein the second diode generates a photocurrent using the first output and the second voltage (Paragraph [0018] – "The optical output 124 may also comprise an SSC for coupling to other optical components. Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120. An input modulation signal, i.e. an analog electrical signal, provided at control input 132, and fed through elements of the control circuitry to the control terminal drive transistor 138 of the driver circuitry of the electro-absorption modulator 120 for modulation of the optical output signal"); and sensing circuitry, wherein in response to the sensing circuitry determining the photocurrent exceeds a threshold, the sensing circuitry causes an adjustment to the second voltage such that an output from the electro-absorption modulated laser is adjusted (Paragraph [0021] – "The second sense means comprises electrical circuitry 150 for detecting the output level of the electro-absorption modulator, e.g. an electrical photocurrent sense element for detecting the absorbed photocurrent of the electro-absorption modulator and generating the second feedback signal, dependent on the output level of the electro-absorption modulator…. That is, the temperature compensated modulation signal is input to a non-inverting input of the differential amplifier, and the second feedback signal is input to an inverting input of the differential amplifier, to generate an error voltage from the difference between the two signals. Thus, the fast feedback control circuitry measures the output optical signal and compares that to the electrical input signal driving the block. The error voltage is generated from the difference between the two signals and is fed to the driver."; Paragraph [0022] – "An electro-optic integrated circuit 200 comprising an electro-optic modulator 220 having monolithically integrated driver and control electronics comprising a fast feedback circuit for linearization and temperature compensation, according to a second embodiment, is shown in FIG. 2.").
Hjartarson does not explicitly teach that the second diode generates a photocurrent using the first output and the second voltage, but one of ordinary skill in the art would recognize that the second voltage impacts the absorption of photons passing through the electro-absorption modulator, which then causes the electro-absorption modulator to generate a photocurrent.
As per claims 2, 9, and 18, Hjartarson teaches claims 1, 8, and 15.
Hjartarson teaches wherein the first voltage is a laser bias voltage (Paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC).") and the second voltage is a modulation voltage (Paragraph [0018] – "The optical output 124 may also comprise a SSC for coupling to other optical components. Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120. An input modulation signal, i.e. an analog electrical signal, provided at control input 132, and fed through elements of the control circuitry to the control terminal drive transistor 138 of the driver circuitry of the electro-absorption modulator 120 for modulation of the optical output signal.").
Hjartarson does not specifically teach that the voltage fed to the first diode is a laser bias voltage. However, one of ordinary skill in the art would recognize that the voltage fed to a laser diode would inherently be a laser bias voltage.
Similarly, Hjartarson does not specifically teach that the voltage fed to the second diode is a modulation voltage, but one of ordinary skill in the art would recognize that the voltage fed to the second diode is a modulation voltage.
As per claims 3, 10, and 19, Hjartarson teaches claims 2, 8, and 18.
Hjartarson teaches wherein the laser bias voltage is held constant (Paragraph [0018] – "The electro-absorption modulator 120 has an optical input 122 for receiving continuous wave (CW) optical input and an optical output 124 for outputting a modulated optical output. For example, the CW optical input may be provided by a discrete or integrated laser diode (not illustrated) that is coupled to the electro-absorption modulator via an optical waveguide and/or a spot size converter (SSC)") and the modulation voltage is varied such that the photocurrent comprises an encoded data transmission (Paragraph [0003] – " Electro-absorption modulators (EAM) are commonly used in the fiber optics world. EAMs are used as external modulators of light output from continuous wave lasers. For example, an EAM can be used with an inexpensive slow laser for a high-performance application, i.e. transmitting at data rates limited, not by the characteristics of the laser, but by the characteristics of the EAM."; Paragraph [0018] – "Electrical terminals 126 and 128 of the electro-optical modulator are provided for applying a reverse DC bias for operation of the electro-absorption modulator 120. An input modulation signal, i.e. an analog electrical signal, provided at control input 132, and fed through elements of the control circuitry to the control terminal drive transistor 138 of the driver circuitry of the electro-absorption modulator 120 for modulation of the optical output signal. The integrated driver and control circuitry forms a fast feedback control loop, comprising a first sense means with a first control loop element, with, for temperature compensation and a second sense means with a second control loop element, for linearization of the electro-absorption modulator.").
Hjartarson does not explicitly teach that the laser bias voltage is held constant. However, one of the ordinary skills in the art would recognize that the laser diode is providing a constant output or a continuous optical wave. Therefore, the input voltage would implicitly be constant as well.
As per claims 4 and 11, Hjartarson teaches claims 1 and 8.
Hjartarson teaches wherein the photocurrent is proportional to an optical waveform output from the electro-absorption modulated laser (FIG. 1, photocurrent sense 150; Paragraph [0021] – "The second sense means comprises electrical circuitry 150 for detecting the output level of the electro-absorption modulator, e.g. an electrical photocurrent sense element for detecting the absorbed photocurrent of the electro-absorption modulator and generating the second feedback signal, dependent on the output level of the electro-absorption modulator."; Paragraph [0025] – "When operating within this range, the input Continuous Wave (CW) light signal can be linearly modulated allowing advanced modulation schemes, such as QPSK (Quadrature Phase Shift Keying), PAM-4 (4-level Pulse Amplitude Modulation) or even QAM (Quadrature Amplitude Modulation), to be applied to the optical signal. For limited reach applications, such as data center interconnect where the path losses and impairments due to dispersion are limited, complex analog modulation of the light signal can be implemented effectively within a limited dynamic range, while providing good error rate performance across the link.").
As per claim 16, Hjartarson teaches claim 15.
Hjartarson teaches outputting an optical signal from an electro-absorption modulated laser associated with the first diode and the second diode based at least on the photocurrent (Paragraph [0021] – "The second sense means comprises electrical circuitry 150 for detecting the output level of the electro-absorption modulator, e.g. an electrical photocurrent sense element for detecting the absorbed photocurrent of the electro-absorption modulator and generating the second feedback signal, dependent on the output level of the electro-absorption modulator…. That is, the temperature compensated modulation signal is input to a non-inverting input of the differential amplifier, and the second feedback signal is input to an inverting input of the differential amplifier, to generate an error voltage from the difference between the two signals. Thus, the fast feedback control circuitry measures the output optical signal and compares that to the electrical input signal driving the block. The error voltage is generated from the difference between the two signals and is fed to the driver.").
Claims 5 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Hjartarson (USPUB 20190238234) in view of Parker (USPUB 20210203126).
As per claims 5 and 12, Hjartarson teaches claims 4 and 11.
Hjartarson teaches that the photocurrent provides feedback to the electro-absorption modulated laser (Paragraph [0021] – "The second sense means comprises electrical circuitry 150 for detecting the output level of the electro-absorption modulator, e.g. an electrical photocurrent sense element for detecting the absorbed photocurrent of the electro-absorption modulator and generating the second feedback signal, dependent on the output level of the electro-absorption modulator…. That is, the temperature compensated modulation signal is input to a non-inverting input of the differential amplifier, and the second feedback signal is input to an inverting input of the differential amplifier, to generate an error voltage from the difference between the two signals. Thus, the fast feedback control circuitry measures the output optical signal and compares that to the electrical input signal driving the block. The error voltage is generated from the difference between the two signals and is fed to the driver.").
Hjartarson does not teach using the feedback to improve the quality of an eye diagram associated with the optical waveform.
However, Parker teaches using feedback to improve the quality of an eye diagram associated with the optical waveform (FIG. 8, Step 806; Paragraph [0052] – "The DC bias voltage may be adjusted until 50% or a target eye crossing is reached (806), where the eye crossing is defined as,
PNG
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110
790
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Greyscale
and Poptical at crossing is the optical power on an eye diagram where the rising 0-to-1 crosses the falling 1-to-0 level optical pattern on an oscilloscope. The eye crossing may be measured on a benchtop oscilloscope tool such as a digital communication analyzer (DCA), or through an eye monitor circuit built into a post-EAM tap. For digital communication, an eye crossing between 40-60% typically provides the highest bit-error-rate for a fixed RF swing voltage and optical power. The fixed insertion loss method requires less measurement time and is roughly correlated to eye crossing; thus, it can provide much faster modulator calibration, but it is less accurate for a specific eye crossing value.").
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the feedback taught by Hjartarson to improve the quality of an eye diagram associated with the optical waveform in light of Parker for the benefit of calibrating the laser as taught by Parker (Paragraph [0053] – "Depending on the approach taken to achieve greater uniformity in the photocurrent density, different calibration sequences may then be performed to determine the operating setpoint of the EAM.").
Claims 6, 13, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Hjartarson (USPUB 20190238234) in view of Nagarajan (USPUB 20180321519).
As per claims 6, 13, and 20, Hjartarson teaches claims 1, 8, and 15.
Hjartarson teaches wherein the photocurrent is used to adjust a bias point associated with the second voltage (Paragraph [0009] – "an optical output for outputting a modulated optical output, and first and second electrical terminals for applying a bias voltage for operating the electro-absorption modulator"; Paragraph [0021] – "The second sense means comprises electrical circuitry 150 for detecting the output level of the electro-absorption modulator, e.g. an electrical photocurrent sense element for detecting the absorbed photocurrent of the electro-absorption modulator and generating the second feedback signal, dependent on the output level of the electro-absorption modulator…. That is, the temperature compensated modulation signal is input to a non-inverting input of the differential amplifier, and the second feedback signal is input to an inverting input of the differential amplifier, to generate an error voltage from the difference between the two signals. Thus, the fast feedback control circuitry measures the output optical signal and compares that to the electrical input signal driving the block. The error voltage is generated from the difference between the two signals and is fed to the driver.").
Hjartarson does not teach that the adjustment is to improve an optical modulation amplitude and an extinction ratio.
However, Nagarajan teaches that optical modulation amplitude and an extinction ratio are known properties (Paragraph [0075] – "In an example, the driver module is coupled to the signal processing blocking using a uni-directional multi-lane bus. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. In an example, the driver interface is configured to transmit output data in either an amplitude modulation format or a combination of phase/amplitude modulation format or a phase modulation format."; Paragraph [0076] – "In an example, the device has a variable bias block configured with the control block. In an example, the variable bias block is configured to selectively tune each of a plurality of laser devices provided on the silicon photonics device to adjust for at least a wavelength of operation, a fabrication tolerance, and an extinction ratio.").
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the adjustment taught by Hjartarson to improve an optical modulation amplitude and an extinction ratio in light of Nagarajan for the benefit of accommodating bias variations as disclosed by Nagarajan (Paragraph [0076] – "In an example, the present bias circuitry accommodates and/or corrects for any bias variations, while desirably controlling power. Of course, there can be variations, modifications, and alternatives.").
Claims 7, 14, and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Hjartarson (USPUB 20190238234) in view of Wu (USPUB 20220179159).
As per claims 7, 14, and 17, Hjartarson teaches claims 1, 8, and 16.
Hjartarson teaches obtaining a reflection of the optical signal (Paragraph [0023] – "The first embodiment shown in FIG. 1 uses the absorbed photo-current to measure the output level. The second embodiment shown in FIG. 2 taps off a small amount of the output optical signal, and detects it using a high-speed photo detector and a TIA. In each case, the feedback circuit measures the output optical signal and compares that to the electrical input signal driving the block.").
Hjartarson does not explicitly disclose a reflection of the optical signal, but one of ordinary skill in the art would recognize that tapping a small amount of an optical signal is a reflection of that optical signal.
Hjartarson does not teach performing an optical alignment of the electro-absorption modulated laser using the photocurrent or the optical signal and the reflected optical signal.
However, Wu teaches using feedback to perform an optical alignment between two photoelectronic elements (Paragraph [0252] – "Each beam-shaping optical element is aligned to cause the laser beam generated by the corresponding laser die to be coupled through the corresponding coupler to the corresponding input waveguide in the photonic integrated circuit. The process of aligning of the beam-shaping optical element is based on the feedback signal generated by the corresponding feedback photodetector. For example, each beam-shaping optical element can be aligned to maximize the coupling of the corresponding laser beam into the corresponding waveguide.").
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the laser taught by Hjartarson to perform an optical alignment of the electro-absorption modulated laser using the photocurrent or the optical signal and the reflected optical signal in light of Wu to improve accuracy as taught by Wu (Paragraph [0204] – "Additionally, the independent adjustability of the lenses 220 enables the fine alignment that is also needed to achieve accurate mode matching. The laser modules 212, lenses 220, prism 230, and photonic integrated circuit 224 are initially aligned in a coarse alignment procedure. Minor variations in the positions and orientations of the components can reduce the amount of light that is coupled into the photonic integrated circuit 224. A fine alignment procedure is used to compensate for such variations.").
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
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Park (USPAT 6717709) discloses an electro absorption modulator in which photocurrent generated by the absorption of light is monitored and bias voltage applied to the electro absorption modulator is varied in order to vary the photocurrent and an extinction ratio of the electro absorption modulator.
Schemmann (USPAT 9479263) discloses systems and methods of minimizing distortion produced when modulating an optical signal using an electrical signal, and further describes a relationship between photocurrent from an electro absorption modulator and distortion of an electro-absorption modulated laser.
Wang (USPUB 20200192129) discloses automatic bias control of an electro-absorption modulator using photocurrent generated by the electro-absorption modulator.
Wang (USPUB 20230129460) discloses automatic bias control of an electro-absorption modulator (EAM) that self-adjusts to detuning changes between the EAM and an optical light source, and further describes a relationship between detuning changes and photocurrent generated by the EAM.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JACOB ETHAN DELA ROSA-FRIO whose telephone number is (571)270-5776. The examiner can normally be reached Monday - Friday, 08:30 - 17:00 EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, David C Payne can be reached at (571) 272-3024. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JACOB ETHAN DELA ROSA-FRIO/Examiner, Art Unit 2635
/OMAR S ISMAIL/Primary Examiner, Art Unit 2635
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