System and method for 400G signal generation and coherent detection

A receiver front end for converting a received multicarrier partial response optical signal into a partial response digital signal;

• an equalizing device for equalizing a pre-filtered full response digital signal;
• a full response carrier recovery device for performing carrier recovery of the signal equalized by the equalizing device;
• and
• a post-filter for post-filtering the signal having undergone carrier recovery by the full response carrier recovery device;
• wherein the front end is operative to perform on the received optical signal blind polarization demultiplexing by a cascaded multi-modulus algorithm, multi-modulus QPSK partitioning frequency offset estimation, and two-stage carrier phase recovery with maximum likelihood phase estimation.

A transmitter for transmitting a plurality of multicarrier optical signals, the transmitter comprising:

• modulators configured to modulate respective polarization components of the plurality of multicarrier optical signals into modulated polarization components;
• combiners configured to combine the respective modulated polarization components of the plurality of optical signals into a plurality of modulated optical signals by T-spaced delay-and-add filtering (T-DAF) to convert a 4-point QPSK signal to 9-point quadrature duobinary signals to change the 2-ASK to 3-ASK vectors, and superimposing the 3-ASK vectors in a complex plane to form 9-QAM signals;
• and
• at least one optical coupler configured to couple the plurality of modulated optical signals into one combined modulated optical signal.

A method for receiving multicarrier signals in an optical communication system, comprising converting a received partial response optical signal into a partial response digital signal, wherein the converting comprises:

• equalizing a pre-filtered full response digital signal by performing multi-modulus blind equalization;
• performing carrier recovery of the equalized signal by FFT and 4th power Viterbi-Viterbi algorithm;
• post-filtering the signal having undergone carrier recovery;
• and
• blind polarization demultiplexing by a cascaded multi-modulus algorithm, multi-modulus QPSK partitioning frequency offset estimation, and two-stage carrier phase recovery with maximum likelihood phase estimation.

An article of manufacture including a computer-readable medium having instructions stored thereon, comprising:

• instructions for causing at least one modulator to modulate respective polarization components of the plurality of multicarrier optical signals into modulated polarization components;
• instructions for causing at least one combiner to combine the respective modulated polarization components of the plurality of multicarrier optical signals into a plurality of modulated optical signals by T-spaced delay-and-add filtering (T-DAF) to convert a 4-point QPSK signal to 9-point quadrature duobinary signals to change the 2-ASK to 3-ASK vectors, and superimposing the 3-ASK vectors in a complex plane to form 9-QAM signals;
• and
• instructions for causing at least one optical coupler to couple the plurality of modulated optical signals into one combined modulated optical signal.

An article of manufacture including a computer-readable medium having instructions stored thereon, comprising instructions for converting a received partial response multicarrier optical signal into a partial response digital signal, said instructions for converting comprising:

• instructions for multi-modulus blind equalization of a pre-filtered full response digital signal;
• instructions for performing carrier recovery of the equalized signal by FFT and 4th power Viterbi-Viterbi algorithm;
• instructions for post-filtering the signal having undergone carrier recovery;
• and
• instructions for blind polarization demultiplexing by a cascaded multi-modulus algorithm, multi-modulus QPSK partitioning frequency offset estimation, and two-stage carrier phase recovery with maximum likelihood phase estimation.