Phase noise reduction of DPSK signals by four wave mixing in a fiber

Differential phase-shift keying (DPSK) format has received attention for long-haul optical fiber communication systems, due to its advantages of improvement in receiver sensitivity high spectral efficiency and robustness to nonlinear effects. Phase noise is the main factor impacting the performance of DPSK system .In this paper , we monitor and reduce nonlinear phase noise by FWM (four-wave mixing) in a fiber, it shows that DPSK signals performance can be improved by an amplitude limiter in a fiber based FWM through reducing nonlinear phase noise.