Research Of The Gordon-Mollenauer Effect In Co-Ofdm System

Nonlinear phase noise, known as the Gordon-Mollenauer (G-M) effect, is caused by the interaction between amplified spontaneous emissions (ASE) noise and fiber Kerr nonlinearity. ASE adds linearly to the signal leading to an amplitude noise that is converted to phase noise through self-phase modulation (SPM). To the phase-modulated system, the nonlinear phase noise can become another important factor to damage the phase signal extremely. G-M noise has been studied extensively about its generation mechanism, the effect to signal and compensation methods after the discovery by Gordon and Mollenauer in1990. But the research of G-M noise in the past is almost limited to single-carrier phase modulation system, for multi-carrier system, in particular, the OFDM system, the nonlinear phase noise effects haven’t been investigated exhaustively.Optical Orthogonal Frequency Division Multiplexing (OFDM) applies the OFDM technology in mobile communications to the optical transmission, which decides that it has the advantages of large capacity, low sensitivity to the GVD and high spectrum efficiency. It will be the focus of the research in utral high speed, large capacity and long distance optical transmission system. And optical OFDM will play an important role in the future information society.Because of its high PAPR and strict requirement for orthogonality, optical OFDM system would be very sensitive to the nonlinear phase noise. Therefore, G-M noise must not be negligible in OOFDM.In this article, the producting mechanism and research status of G-M effect in Optical OFDM system are introduced clearly. Then, the performance and characteristics of G-M effect in optical OFDM under different parameter settings were deeply investigated by constructing the simulation platforms. Some major research contents and achievements are summarized as follow:(1) First, starting from the research on the mechanism of G-M noise, the nonlinear phase noise in OFDM system is analyzed deeply through formula derivation and fundamental theories.(2) According to the essence and characteristic of G-M effect, the simulation method of G-M noise is explored. Through the separation of the nonlinear phase noise from the other noise in links, the influence of the G-M on signal under different conditions can be observed clearly.(3) Based on the simulation platform constructed by using the Matlab simulation tools, the G-M effect in112Gbit/s polarization division multiplexing OFDM (PDM-OFDM) is researched systematically and compared with the PDM-QPSK signal at the same bit rate.(4) The effect and characteristic of G-M noise on CO-OFDM system and QPSK system are summarized, combined with simulation results and theoretical analysis.