# US 10,374,702 B1 · Methods and apparatus for predicting and monitoring performance of a coherent optical transceiver at various baud rates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,702 B1 - Document ID: US10374702B1 - Status: Granted - Kind: B1 - Application number: 15/858,364 - Filed: 2017-12-29 - Granted: 2019-08-06 - Earliest claimed: 2017-12-29 - Assignees: Juniper Networks, Inc. - Applicants: Juniper Networks, Inc. - Inventors: Yang Yue; Qiang Wang; Xuan He - Web page: https://patentgrep.com/patent/US10374702B1 ## CPC - H04B 10/07953: {Monitoring or measuring OSNR, BER or Q} - H04B 10/40: Transceivers - H04B 10/07955: {Monitoring or measuring power} - H04Q 11/00: Selecting arrangements for multiplex systems (multiplex systems H04J) - H04B: TRANSMISSION - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract In some embodiments, an apparatus includes an optical transceiver having a photo diode and a processor configured to be operatively coupled to the photo diode. The photo diode is configured to measure a set of receiver optical power (ROP) values at a set of baud rate values. The processor is configured to measure a set of bit error rate (BER) values of a digital modulated signal at the set of baud rate values. The processor is configured to determine an estimated optical signal noise ratio (OSNR) value at a baud rate value from the set of baud rate values based on the set of ROP values and the set of BER values. The processor is configured to send a signal indicating the estimated OSNR value at the baud rate value such that a planned route is selected to send data signals based on the estimated OSNR value. ## Claims ### Claim 1 An apparatus, comprising: an optical transceiver configured to be operatively coupled to a network, the optical transceiver including a photo diode and a processor configured to be operatively coupled to the photo diode, the photo diode configured to measure a plurality of receiver optical power (ROP) values at a plurality of baud rate values and send the plurality of ROP values to the processor, the processor configured to measure a plurality of bit error rate (BER) values of a digital modulated signal at the plurality of baud rate values at an input port of the optical transceiver, the processor configured to determine an estimated optical signal noise ratio (OSNR) value at a baud rate value from the plurality of baud rate values at the input port of the optical transceiver based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values, the processor configured to send a signal indicating the estimated OSNR value at the baud rate value such that a planned route is selected to send data signals based on the estimated OSNR value. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein: the optical transceiver is configured to modulate optical signals in a modulation format from a plurality of modulation formats including polarization-multiplexed 16-quadrature amplitude modulation (PM-16QAM). ### Claim 3 (depends on 1) The apparatus of claim 1, wherein: the plurality of baud rate values is within a range of about 32 GHz to 86 GHz. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein: during a design verification test of the optical transceiver, a transmitter of the optical transceiver is configured to be connected to a receiver of the optical transceiver through at least one of (1) an optical switch integrated within the optical transceiver, or (2) an external loop-back connection. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein: the processor is configured to receive a signal indicating a chromatic dispersion (CD) value, a differential group delay (DGD) value, or a carrier frequency offset (CFO) value, the processor is configured to improve accuracy of the estimated OSNR value at the baud rate value based on at least one of the CD value, the DGD value, or the CFO value. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein: the processor is configured to determine a plurality of bandwidth parameter values at the plurality of baud rate values based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values; the processor is configured to determine the estimated OSNR value at the baud rate value based on the plurality of bandwidth parameter values at the plurality of baud rate values. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the processor is configured to determine the plurality of bandwidth parameter values during one of a design verification test of the optical transceiver or an in-field measurement of the optical transceiver. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein: the processor is configured to determine a plurality of noise floor parameter values at the plurality of baud rate values based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values; the processor is configured to determine the OSNR value at the baud rate value based on the plurality of noise floor parameter values at the plurality of baud rate values. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein: the signal is a first signal, the processor is configured to send a second signal when the estimated OSNR value at the baud rate value meets a criteria such that the optical transceiver is reconfigured. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the processor is configured to not send the data signals. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the processor is configured to receive the digital modulated signal at the input port of the optical transceiver via a coherent detection. ### Claim 12 An apparatus, comprising: an optical transceiver configured to be operatively coupled to a network, the optical transceiver including a variable optical attenuator (VOA) and a processor operatively coupled to the VOA, the VOA configured to vary a receiver optical power (ROP) parameter to obtain a plurality of ROP values at a plurality of baud rate values, the processor configured to measure a plurality of bit error rate (BER) values in response to the plurality of ROP values at the plurality of baud rate values, the processor configured to estimate a plurality of optical signal noise ratio (OSNR) values at the plurality of baud rate values based on the plurality of BER values and the plurality of ROP values, the processor configured to send a signal when an OSNR value from the plurality of OSNR values meets a criteria such that the optical transceiver is reconfigured. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the optical transceiver is configured to modulate optical signals in a modulation format from a plurality of modulation formats including polarization-multiplexed 16-quadrature amplitude modulation (PM-16QAM). ### Claim 14 (depends on 12) The apparatus of claim 12, wherein: the processor is configured to determine a plurality of bandwidth parameter values at the plurality of baud rate values based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values; the processor is configured to estimate the plurality of OSNR values at the plurality of baud rate values based on the plurality of bandwidth parameter values at the plurality of baud rate values. ### Claim 15 (depends on 12) The apparatus of claim 12, wherein: the processor is configured to determine a plurality of noise floor parameter values at the plurality of baud rate values based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values; the processor is configured to estimate the plurality of OSNR values at the plurality of baud rate values based on the plurality of noise floor parameter values at the plurality of baud rate values. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the processor is configured to determine the plurality of noise floor parameter values during one of a design verification testing of the optical transceiver or an in-field measurement of the optical transceiver. ### Claim 17 (depends on 12) The apparatus of claim 12, wherein: the processor is configured to receive a signal indicating a chromatic dispersion (CD) value, a differential group delay (DGD) value, or a carrier frequency offset (CFO) value, the processor is configured to improve accuracy of the plurality of OSNR values based on at least one of the CD value, the DGD value, or the CFO value. ### Claim 18 (depends on 12) The apparatus of claim 12, wherein the processor is configured to determine the plurality of OSNR values at the plurality of baud rate values without additional hardware. ### Claim 19 (depends on 12) The apparatus of claim 12, wherein: the signal is a first signal; the criteria is a first criteria; the processor is configured to send a second signal when an OSNR value from the plurality of OSNR values meets a second criteria such that a planned route is selected to send data signals based on the OSNR value. ### Claim 20 (depends on 12) The apparatus of claim 12, wherein: a transmitter of the optical transceiver is configured to be connected to a receiver of the optical transceiver through at least one of (1) an optical switch integrated within the optical transceiver, or (2) an external loop-back connection. ### Claim 21 A method, comprising: measuring a plurality of receiver optical power (ROP) values of an optical transceiver at a plurality of baud rates, the optical transceiver configured to be operatively coupled to a network, a transmitter of the optical transceiver connected to a receiver of the optical transceiver during a design verification test of the optical transceiver; measuring a plurality of bit error rate (BER) values at the plurality of baud rates at an input port of the optical transceiver; determining an estimated optical signal noise ratio (OSNR) value at a baud rate from the plurality of baud rates at the input port of the optical transceiver based on the plurality of ROP values and the plurality of BER values; and sending a signal indicating the estimated OSNR value at the baud rate such that a planned route is selected to send data signals based on the estimated OSNR value at the baud rate. ### Claim 22 An apparatus, comprising: a memory; and a processor operatively coupled to the memory, the processor configured to be operatively coupled to a photo diode of an optical transceiver, the processor configured to receive a plurality of receiver optical power (ROP) values at a plurality of baud rate values from the photo diode, the processor configured to measure a plurality of bit error rate (BER) values of a digital modulated signal at the plurality of baud rate values, the processor configured to determine an estimated optical signal noise ratio (OSNR) value at a baud rate value from the plurality of baud rate values based on the plurality of ROP values at the plurality of baud rate values and the plurality of BER values at the plurality of baud rate values, the processor configured to send a signal indicating the estimated OSNR value at the baud rate value such that a planned route is selected to send data signals based on the estimated OSNR value.