# US 10,320,483 B2 · Optical communication system, optical receiver, optical receiver control method, and non-transitory computer readable medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,320,483 B2 - Document ID: US10320483B2 - Status: Granted - Kind: B2 - Application number: 15/991,852 - Filed: 2018-05-29 - Published: 2018-12-06 - Granted: 2019-06-11 - Earliest claimed: 2013-07-11 - Assignees: NEC Corporation - Applicants: NEC Corporation - Inventors: Yasushi Hara - Web page: https://patentgrep.com/patent/US10320483B2 ## CPC - H04B 10/2507: for the reduction or elimination of distortion or dispersion - H04B 10/5561: {Digital phase modulation} - H04B 10/612: {for optical signals modulated with a format different from binary or higher-order PSK [X-PSK], e.g. QAM, DPSK, FSK, MSK, ASK} - H04B 10/614: {comprising one or more polarization beam splitters, e.g. polarization multiplexed [PolMux] X-PSK coherent receivers, polarization diversity heterodyne coherent receivers (H04J14/06 takes precedence)} - H04B 10/616: {Details of the electronic signal processing in coherent optical receivers} - H04B 10/6161: {Compensation of chromatic dispersion} - H04L 27/2096: {Arrangements for directly or externally modulating an optical carrier (optical modulation H04B10/503)} - H04L 27/3809: {Amplitude regulation arrangements} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Present invention provides an optical communication system that controls reception sensitivity of an optical receiver. The communication system (100) according to the present invention comprising: an optical transmitter (1) to which an transmission signal is input, and which modulates the transmission signal to an optical signal and transmits the optical signal; and an optical receiver (2) that receives the optical signal and demodulates the optical signal to an transmission signal. And the optical receiver (2) includes a photoelectric conversion means (10) for converting the optical signal into an analog electric signal, a conversion and demodulation means (25) for converting the analog electric signal into a digital signal and demodulating the signal to the transmission signal, and an amplitude control means (102) for controlling amplitude of the analog electric signal, and the amplitude control means (102) controls the amplitude of the analog electric signal in accordance with wavelength dispersion of the optical signal. ## Claims ### Claim 1 A communication system comprising: an optical transmitter to which a transmission signal is input, and which modulates the transmission signal to an optical signal and transmits the optical signal; and an optical module that receives the optical signal and demodulates the optical signal to the transmission signal, wherein the optical module includes a photoelectric converter configured to convert the optical signal into an analog electric signal, an analog digital converter configured to convert the analog electric signal into a digital signal, a digital signal processor configured to process the digital signal, and a controller configured to receive an amplitude value of the analog electric signal and a wavelength dispersion value of the optical signal, and wherein the controller is further configured to control an amplitude of the analog electric signal based on the amplitude value and a reference amplitude value based on the wavelength dispersion value. ### Claim 2 (depends on 1) The communication system according to claim 1, wherein the controller is further configured to control the amplitude of the analog electric signal to become smaller as the wavelength dispersion value is increased. ### Claim 3 (depends on 1) The communication system according to claim 1, wherein the photoelectric converter includes an amplifier that is configured to amplify the analog electric signal input to the analog digital converter, and the controller is further configured to estimate the wavelength dispersion value and determine, based on the estimated wavelength dispersion value, the reference amplitude value for controlling a gain of the amplifier. ### Claim 4 An optical module comprising: a photoelectric converter configured to convert an optical signal into an analog electric signal; an analog digital converter configured to convert the analog electric signal into a digital signal; a digital signal processor configured to process the digital signal; and a controller configured to receive an amplitude value of the analog electric signal and a wavelength dispersion value of the optical signal, wherein the controller is further configured to control an amplitude of the analog electric signal based on the amplitude value and a reference amplitude value based on the wavelength dispersion value. ### Claim 5 (depends on 4) The optical receiver according to claim 4, wherein the controller is further configured to control the amplitude of the analog electric signal to become smaller as the wavelength dispersion value of the optical signal is increased. ### Claim 6 (depends on 4) The optical receiver according to claim 4, wherein the photoelectric converter includes an amplifier that is configured to amplify the analog electric signal input to the analog digital converter, and the controller is further configured to estimate the wavelength dispersion value and determine, based on the estimated wavelength dispersion value, the reference amplitude value for controlling a gain of the amplifier. ### Claim 7 An optical module control method, wherein the optical module receiver performs operations comprising: converting an optical signal into an analog electric signal; converting the analog electric signal into a digital signal; processing the digital signal; receiving an amplitude value of the analog electronic signal and a wavelength dispersion value of the optical signal; demodulating the optical signal to a transmission signal; and controlling an amplitude of the analog electric signal based on the amplitude value and a reference amplitude value based on the wavelength dispersion value. ### Claim 8 (depends on 7) The optical module control method according to claim 7, wherein the controlling includes controlling the amplitude of the analog electric signal to become smaller as the wavelength dispersion value is increased. ### Claim 9 (depends on 7) The optical module control method according to claim 7, wherein the optical module includes an amplifier that is configured to amplify the analog electric signal input to the analog digital converter, and the controlling includes estimating the wavelength dispersion value and determining, based on the estimated wavelength dispersion value, the reference amplitude value for controlling a gain of the amplifier.