Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-2, 8 are rejected under 35 U.S.C. 103 as being unpatentable over KIKUCHI, Kazuro, ("Fundamentals of Coherent Optical Fiber Communications", Journal of Lightwave Technology, 03 August 2015, vol. 34, issue 1, pp. 157-179, p. 159) in view of ZHANG, Boyang et al., ("Analog Signal Processing Circuits for a 400Gb/s 16QAM Optical Coherent Receiver", 2021 IEEE International Symposium on Circuits and Systems (ISCAS), 22 May 2021, pp. 1-5, pp. 1-5).
With regards to claims 1, 2, 8 Kikuchi teaches an acquirer (corresponding to the acquisition unit, implicitly taught, that acquires the data in fig. 2(b)) that acquires an electrical signal (corresponding to the data in fig. 2(b)) obtained by converting an optical signal (corresponding to the optical signal in fig. 2(a)) by coherent detection, the optical signal having been transmitted from a transmission unit after having been obtained by converting a digital modulation signal (corresponding to the digital modulation signal in fig. 15) by phase modulation or by quadrature amplitude modulation, then dividing the signal between multiple carrier waves (corresponding to the output, divided into two channels, from the DACs in the DSP of the DSP-based optical transmitter in fig. 2 (a); additionally corresponding to the "two-channel analog signals" that modulate the IQ components described in "At the transmitter, after appropriate DSP, digital data are converted into two-channel analog signals by digital-to-analog converters (DACs), which modulate IQ components of the RF carrier." (page 159, left column, lines 45-47)), and superimposing the signals on a local oscillator laser (corresponding to the "optical carrier" in fig. 2(a)); and a compensator (corresponding to the FDE and the adaptive equalizer illustrated in fig. 18) that compensates for the multiple signals respectively superimposed on the multiple carrier waves obtained from the acquired electrical signal. Kikuchi does not specifically teach a crosstalk compensator. Zhang teaches a multi-carrier signal waveform equalization circuit (corresponding to the equalizer in "The function of equalizer is to eliminate chromatic dispersion (CD), polarization crosstalk (PC) in optical fibers and high frequency attenuation induced by electronic devices." (page 1, right column, lines 2-4), the equalizer in fig. 1, the PC equalizer in fig. 2, etc.) provided with a crosstalk compensator unit that compensates for crosstalk between multiple signals respectively superimposed on the multiple carrier waves obtained from the acquired electrical signal, and other compensation units. It would have been obvious to one of ordinary skill in the art to combine Kikuchi with Zhang for the purpose of implementing crosstalk compensation. The motivation being to lower OSNR and improve bit error rate.
With regards to claim 2, although Zhang discloses an analog processing unit, official notice is taken that a person skilled in the art could implement the same in a digital circuit (digital filter). Official notice is taken that it is well known in the art A crosstalk compensator can indeed include a digital filter —in fact, many modern designs rely on digital filtering for precise, flexible, and high-performance crosstalk cancellation.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over KIKUCHI, Kazuro, ("Fundamentals of Coherent Optical Fiber Communications", Journal of Lightwave Technology, 03 August 2015, vol. 34, issue 1, pp. 157-179, p. 159) in view of ZHANG, Boyang et al., ("Analog Signal Processing Circuits for a 400Gb/s 16QAM Optical Coherent Receiver", 2021 IEEE International Symposium on Circuits and Systems (ISCAS), 22 May 2021, pp. 1-5, pp. 1-5) as applied to claim 1-2 and further in view of Matsuda et al. (2016/0241352).
With regards to claim 3, Kikuchi in view of Zhang fails to teach the multi-carrier signal waveform equalization circuit according to claim 2, further comprising: a phase compensator that is arranged in a preceding stage of the crosstalk compensator or in both of a preceding stage and a subsequent stage of the crosstalk compensator, and compensates for phase rotation of a signal. This feature is taught by Matsuda. (Fig, 2, phase rotation compensation). It would have been obvious to one of ordinary skill in the art to place the phase rotator compensator ahead of crosstalk compensator in order to allow phase alignment before crosstalk correction. Thus ensuring that the compensator operates on a well-synchronized signal.
Claim 4-5 are rejected under 35 U.S.C. 103 as being unpatentable over KIKUCHI, Kazuro, ("Fundamentals of Coherent Optical Fiber Communications", Journal of Lightwave Technology, 03 August 2015, vol. 34, issue 1, pp. 157-179, p. 159) in view of ZHANG, Boyang et al., ("Analog Signal Processing Circuits for a 400Gb/s 16QAM Optical Coherent Receiver", 2021 IEEE International Symposium on Circuits and Systems (ISCAS), 22 May 2021, pp. 1-5, pp. 1-5) as applied to claim 1-2 and further in view of Matsuda et al. (2016/0241352) and Oota(2015/0180586)
With regards to claim 4, Oota teaches the multi-carrier signal waveform equalization circuit according to claim 2, further comprising a waveform distortion compensation unit compensator that is arranged in a preceding stage of the crosstalk compensation unit compensator, and compensates for linear distortion other than distortion to be compensated by the crosstalk compensation. This feature is taught by Oota (Fig, 1@111)). It would have been obvious to one of ordinary skill in the art to place the waveform distortion compensator ahead of crosstalk compensator in order reduce signal non0linearirity, improve signal integrity. It can also lower the overall crosstalk level, reducing the load on the crosstalk compensator
With regards to claim 5, Oota fails to teach the multi-carrier signal waveform equalization circuit according to claim 4, wherein the waveform distortion compensator includes a digital filter. Official notice is taken that it is well known in the art that a waveform distortion compensator often does include a digital filter, especially when high precision, adaptability, and real-time correction are required. Digital filters are well-suited for this role because they can be precisely tuned, updated dynamically, and integrated into modern DSP-based systems.
Allowable Subject Matter
Claims 6-7 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Conclusion
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/KENNETH N VANDERPUYE/Supervisory Patent Examiner, Art Unit 2634
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