Leveraging coherent detection to measure performance of optical transmitter

An apparatus comprising:

• a coherent optical receiver configured to receive an optical signal from an optical transmitter and to perform coherent optical-to-electrical detection of the optical signal to produce an in-phase receive signal and a quadrature receive signal;
• and
• a computing device coupled to the coherent optical receiver, the computing device configured to:
• emulate a worst-case configuration of an optical fiber with which the optical transmitter is to be used, based on the in-phase receive signal and quadrature receive signal to produce a noise contribution associated with the worst-case configuration of the optical fiber by deriving a chirp contribution associated with the optical transmitter based on the in-phase receive signal and the quadrature receive signal, and
• determine a figure of merit of the optical transmitter based on the noise contribution.

One or more non-transitory computer readable storage media comprising instructions that when executed configure a coherent optical receiver and a computing device to perform operations comprising:

• obtaining, by the coherent optical receiver, an optical signal output by an optical transmitter;
• performing, via the coherent optical receiver, coherent optical-to-electrical detection of the optical signal to produce an in-phase receive signal and a quadrature receive signal;
• emulating, by the computing device, a worst-case configuration of an optical fiber with which the optical transmitter is to be used, based on the in-phase receive signal and the quadrature receive signal to produce a noise contribution associated with the worst-case configuration of the optical fiber, wherein emulating the worst-case configuration of the optical fiber includes deriving a chirp contribution associated with the optical transmitter based on the in-phase receive signal and the quadrature receive signal;
• and
• determining a figure of merit of the optical transmitter based on the noise contribution.

A method comprising:

• obtaining an optical signal output by an optical transmitter;
• performing coherent optical-to-electrical detection of the optical signal to produce an in-phase receive signal and a quadrature receive signal;
• emulating, by a computing device, a worst-case configuration of an optical fiber with which the optical transmitter is to be used, based on the in-phase receive signal and the quadrature receive signal to produce a noise contribution associated with the worst-case configuration of the optical fiber;
• determining, by the computing device, a figure of merit of the optical transmitter based on the noise contribution, wherein the figure of merit is a transmitter dispersion eye closure quaternary (TDECQ) value;
• comparing the TDECQ value to a threshold to determine whether performance of the optical transmitter meets a compliance value;
• and
• based on determining that the performance of the optical transmitter does not meet the compliance value, changing a configuration of the optical transmitter.