# US 2021/0242943 A1 · Optical signal processing method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242943 A1 - Document ID: US20210242943A1 - Status: Published application - Kind: A1 - Application number: 17/239,872 - Filed: 2021-04-26 - Published: 2021-08-05 - Earliest claimed: 2018-10-29 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Shiyi CAO - Web page: https://patentgrep.com/patent/US20210242943A1 ## CPC - H04B 10/0775: {Performance monitoring and measurement of transmission parameters} - H04B 10/2972: {Each direction being amplified separately} - H04B 10/2537: due to scattering processes, e.g. Raman or Brillouin scattering - H04B 10/40: Transceivers - H01S 3/06787: {Bidirectional amplifier} - H04B 10/071: using a reflected signal, e.g. using optical time domain reflectometers [OTDR] - H04B: TRANSMISSION - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract An optical signal processing method and apparatus. The method includes: obtaining a first sending signal, where the first sending signal is a signal that is sent by a first transmitter to a second receiver through a first optical fiber; determining estimation information of a backward optical signal based on the first sending signal; the backward optical signal is generated during transmission of the first sending signal, the backward optical signal is transmitted through at least one fiber section in the first optical fiber, and a transmission direction of the backward optical signal is opposite to a transmission direction of the first sending signal; and obtaining a second sending signal based on the estimation information of the backward optical signal. According to the embodiments, impact of the backward optical signal on effective signal transmission can be reduced, and a signal-to-noise ratio can be improved. ## Claims ### Claim 1 An optical signal processing method, comprising: obtaining a first sending signal, wherein the first sending signal is a signal that is sent by a first transmitter to a second receiver through a first optical fiber; determining estimation information of a backward optical signal based on the first sending signal, wherein the backward optical signal is generated during transmission of the first sending signal, the backward optical signal is transmitted through at least one fiber section in the first optical fiber, and a transmission direction of the backward optical signal in the at least one fiber section is opposite to a transmission direction of the first sending signal; and obtaining a second sending signal based on the estimation information of the backward optical signal, wherein the second sending signal is a signal sent by a second transmitter to a first receiver through a second optical fiber, and at least a part of the first optical fiber and a part of the second optical fiber overlap; and in the overlapping part of optical fibers, the transmission direction of the first sending signal is opposite to a transmission direction of the second sending signal. ### Claim 2 (depends on 1) The method according to claim 1, wherein the obtaining of the second sending signal based on the estimation information of the backward optical signal comprises: obtaining a coherent received signal, wherein the coherent received signal is obtained by the first receiver in a coherent receiving manner; and obtaining the second sending signal based on the coherent received signal and the estimation information of the backward optical signal. ### Claim 3 (depends on 1) The method according to claim 1, wherein the backward optical signal is a Rayleigh backscattering signal. ### Claim 4 (depends on 1) The method according to claim 1, wherein the first sending signal comprises first sending signals at multiple preset times before a current moment, and the determining of estimation information of a backward optical signal based on the first sending signal comprises: separately multiplying the first sending signals at the multiple preset times by a corresponding first coefficient, to obtain multiple first intermediate signals; determining the estimation information of the backward optical signal based on the multiple first intermediate signals; and the first sending signal at each preset time corresponds to one first coefficient; and the first coefficient is related to any one or more of a strength attenuation coefficient, a propagation coefficient, a group velocity, and a Rayleigh backscattering coefficient when the optical signal is transmitted in the optical fiber. ### Claim 5 (depends on 4) The method according to claim 4, further comprising: determining second intermediate signals at the multiple preset times based on the first sending signals at the multiple preset times and the strength attenuation coefficient and the propagation coefficient when the optical signal is transmitted in the optical fiber; and the separately multiplying of the first sending signals at the multiple preset times by a corresponding first coefficient, to obtain the multiple first intermediate signals comprises: separately multiplying the second intermediate signals at the multiple preset times by the corresponding first coefficient to obtain the multiple first intermediate signals. ### Claim 6 (depends on 4) The method according to claim 4, wherein an effective length of the first optical fiber is L, the multiple preset times are N preset times, an interval between adjacent preset times is ΔT, ΔT, and ΔT is the group velocity; the effective length of the first optical fiber is not greater than a length of the first optical fiber; and the separately multiplying of the first sending signals at the multiple preset times by a corresponding first coefficient to obtain the multiple first intermediate signals comprises: separately multiplying the first sending signals at the N preset times by the corresponding first coefficient to obtain N first intermediate signals; wherein N is a positive integer. ### Claim 7 (depends on 4) The method according to claim 4, wherein at least one optical amplifier is disposed in the first optical fiber, the at least one optical amplifier divides the first optical fiber into at least two optical amplifier regenerator sections, and the multiple preset times comprise multiple preset times corresponding to each optical amplifier regenerator section; and the separately multiplying of the first sending signals at the multiple preset times by a corresponding first coefficient, to obtain the multiple first intermediate signals comprises: separately multiplying first sending signals at the multiple preset times corresponding to each optical amplifier regenerator section by the corresponding first coefficient to obtain the multiple first intermediate signals. ### Claim 8 (depends on 7) The method according to claim 7, further comprising: correcting or updating the first coefficient based on a bit error rate, before bit error correction is performed, used when the second sending signal is obtained. ### Claim 9 (depends on 7) The method according to claim 7, further comprising: correcting or updating, in a preset time window, the first coefficient based on the estimation information of the backward optical signal, and stopping, by the second transmitter in the preset time window, sending the second sending signal. ### Claim 10 An optical signal processing apparatus, wherein the optical signal processing apparatus serves as a first receiver, and the apparatus comprises: one or more processors, and a storage medium configure to store program instructions; wherein, when executed by the one or more processors, the instructions cause the device to: obtain a first sending signal, wherein the first sending signal is a signal that is sent by a first transmitter to a second receiver through a first optical fiber; determine estimation information of a backward optical signal based on the first sending signal, wherein the backward optical signal is generated during transmission of the first sending signal, the backward optical signal is transmitted through at least one fiber section in the first optical fiber, and a transmission direction of the backward optical signal in the at least one fiber section is opposite to a transmission direction of the first sending signal; and obtain a second sending signal based on the estimation information of the backward optical signal, wherein the second sending signal is a signal sent by a second transmitter to a first receiver through a second optical fiber, and at least a part of the first optical fiber and a part of the second optical fiber overlap; and in the overlapping part of optical fibers, the transmission direction of the first sending signal is opposite to a transmission direction of the second sending signal. ### Claim 11 (depends on 10) The apparatus according to claim 10, wherein when executed by the one or more processors, the instructions further cause the apparatus to: obtain a coherent received signal, wherein the coherent received signal is obtained by the first receiver in a coherent receiving manner; and obtain the second sending signal based on the coherent received signal and the estimation information of the backward optical signal. ### Claim 12 (depends on 10) The apparatus according to claim 10, wherein the backward optical signal is a Rayleigh backscattering signal. ### Claim 13 (depends on 10) The apparatus according to claim 10, wherein the first sending signal comprises first sending signals at multiple preset times before a current moment, and when executed by the one or more processors, the instructions further cause the apparatus to: separately multiply the first sending signals at the multiple preset times by a corresponding first coefficient, to obtain multiple first intermediate signals; determine the estimation information of the backward optical signal based on the multiple first intermediate signals; the first sending signal at each preset time corresponds to one first coefficient; and the first coefficient is related to any one or more of a strength attenuation coefficient, a propagation coefficient, a group velocity, and a Rayleigh backscattering coefficient when the optical signal is transmitted in the optical fiber. ### Claim 14 (depends on 13) The apparatus according to claim 13, wherein when executed by the one or more processors, the instructions further cause the apparatus to: determine second intermediate signals at the multiple preset times based on the first sending signals at the multiple preset times and the strength attenuation coefficient and the propagation coefficient when the optical signal is transmitted in the optical fiber; and separately multiply the second intermediate signals at the multiple preset times by the corresponding first coefficient, to obtain the multiple first intermediate signals. ### Claim 15 (depends on 14) The apparatus according to claim 14, wherein an effective length of the first optical fiber is L, the multiple preset times are N preset times, an interval between adjacent preset times is v, v, and v is the group velocity; the effective length of the first optical fiber is not greater than a length of the first optical fiber; the processing unit is configured to separately multiply the first sending signals at the N preset times by the corresponding first coefficient, to obtain N first intermediate signals; wherein N is a positive integer. ### Claim 16 (depends on 14) The apparatus according to claim 14, wherein at least one optical amplifier is disposed in the first optical fiber, the at least one optical amplifier divides the first optical fiber into at least two optical amplifier regenerator sections, and the multiple preset times comprise multiple preset times corresponding to each optical amplifier regenerator section; and, when executed by the one or more processors, the instructions further cause the apparatus to: separately multiply first sending signals at the multiple preset times corresponding to each optical amplifier regenerator section by the corresponding first coefficient, to obtain the multiple first intermediate signals. ### Claim 17 (depends on 13) The apparatus according to claim 13, wherein, when executed by the one or more processors, the instructions further cause the apparatus to: correct or update the first coefficient based on a bit error rate, before bit error correction is performed, used when the second sending signal is obtained. ### Claim 18 (depends on 13) The apparatus according to claim 13, wherein, when executed by the one or more processors, the instructions further cause the apparatus to: correct or update, in a preset time window, the first coefficient based on the estimation information of the backward optical signal, and stop, in the preset time window, sending the second sending signal. ### Claim 19 (canceled) ### Claim 20 A non-transitory computer-readable storage medium having a program recorded thereon; wherein the program makes the computer execute a method comprising: obtaining a first sending signal, wherein the first sending signal is a signal that is sent by a first transmitter to a second receiver through a first optical fiber; determining estimation information of a backward optical signal based on the first sending signal, wherein the backward optical signal is generated during transmission of the first sending signal, the backward optical signal is transmitted through at least one fiber section in the first optical fiber, and a transmission direction of the backward optical signal in the at least one fiber section is opposite to a transmission direction of the first sending signal; and obtaining a second sending signal based on the estimation information of the backward optical signal, wherein the second sending signal is a signal sent by a second transmitter to a first receiver through a second optical fiber, and at least a part of the first optical fiber and a part of the second optical fiber overlap; and, in the overlapping part of optical fibers, the transmission direction of the first sending signal is opposite to a transmission direction of the second sending signal.