An effective carrier phase estimation scheme in faster than Nyquist WDM transmission system

We propose a carrier phase estimation method using unequaled digital pilot tone in a faster than Nyquist WDM transmission system, in which the digital pilot tone is employed to estimate laser phase noise induced by the lasers located at the transmitter and the receiver ends. The method can effectively overcome the scale of the inter-symbol interference introduced by FTN signaling, with the good features of high phase noise tolerance and simple hardware complexity.