Channel diagnostics based on equalizer coefficients

A system for generating channel diagnostics information, the system comprising:

• an optical front end configured to receive an optical signal and convert the optical signal to an analog signal vector;
• an analog front end configured to generate a digital signal vector from the analog signal vector;
• a matrix rotator configured to generate a polarized digital signal vector from the digital input signal vector;
• a first adaptive equalizer configured to generate a first equalized signal vector from the polarized digital signal vector, and to adaptively generate first equalizer coefficients from the polarized digital signal vector;
• a channel diagnostics block configured to generate the channel diagnostics information from the first equalizer coefficients;
• a second adaptive equalizer configured to generate a second equalized signal vector from the digital input signal vector;
• a demodulator configured to generate a demodulated signal from the second equalized signal vector;
• a decoder configured to generate a decoded signal from the demodulated signal;
• and
• a framer configured to format the decoded signal for a host interface, and to detect an equalizer-induced differential group delay in the decoded signal.

A method for generating channel diagnostics information in a communication system, the method comprising:

• receiving a digital input signal vector;
• generating, by a matrix rotator, a polarized digital signal vector from the digital input signal vector;
• generating, by a first adaptive equalizer, a first equalized signal vector from the polarized digital signal vector;
• adaptively generating, by the first adaptive equalizer, first equalizer coefficients from the polarized digital signal vector;
• generating, by the channel diagnostics block, channel diagnostics information from the first equalizer coefficients;
• and
• generating, by a second adaptive equalizer, a second equalized signal vector from the digital input signal vector.