200G self-homodyne detection with 64QAM by endless optical polarization demultiplexing

This paper investigates the self-homodyne detection system with orthogonal polarization between pilot and signal (oSHD) through optical polarization demultiplexing of carrier and signal at receiver. Compared to digital demultiplexing, optical demultiplexing provides around a 0.9dB benefit in receiver sensitivity. The impact of crosstalk due to optical demultiplexing has been investigated in terms of carrier-to-signal power ratio, and delay between signal and carrier. Results show that the oSHD system is very tolerant to crosstalk, with a negligible penalty for crosstalk up to -22dB. Experiments were carried out to evaluate the system performance, including polarization tracking performance, long term stability, bit error rate performance, and tolerance to laser linewidth and delay between signal and pilot. 41Gbaud 64QAM oSHD with 200Gb/s net data rate has been realized by using the scheme with receiver sensitivity better than -4dBm, providing a promising candidate solution for 800Gb/s Ethernet.