Noise Reduction of a Novel Phase-Locked Coherent Optical Phase Demodulator

This paper includes the novel cancellation technique for reducing phase noise and shot noise with the relaxation of stringent line width requirements and power requirements of optical sources in proposed phase-locked coherent demodulator for phase modulated analog optical link. The theoretical analysis has been carried out considering finite loop propagation delay and additional phase modulation at LO laser output. The technique of cancellation significantly compensates effect of loop propagation delay and improves line width requirement up to 29.6%. Furthermore, the nonlinear tracking of LO phase modulation reduces power requirement to 2.8dBm in terms of PNB.