Application Of Optical Nonlinear Compensator In High-speed Coherent Optical Communication System

As an information transmission technology based on optical carrier,high speed and large capacity have always been the goals pursued during the development of optical fiber communication technology.With the increasing number of Internet users,an urgent need has been raised for the improvement of bandwidth utilization..Although the attenuation of optical power in optical fiber links has been effectively compensated with the advent of erbium-doped fiber amplifier(EDFA),the dispersion and non-linearity effects are still important impediments to the increase of communication rates.In this paper,two kinds of optical nonlinear compensators—NDF nonlinear compensator and DPF nonlinear compensator—were used to realize the nonlinear compensation of 100 G PM-QPSK high-speed coherent optical communication systems.Optical fiber communication software Optsim was used to build the traditional optical dispersion compensation link and non-linear compensation link based on predispersion compensation.The performance of the two links was respectively performed through simulation.The first kind of optical nonlinear compensation technology is NDF nonlinear compensation based on the predistortion compensation.This technique mainly uses the phenomenon that the optical carrier broadens into a flat top due to the group velocity dispersion and Kerr effect in the NDF fiber.By adding an NDF optical nonlinear compensator,the BER can be achieved at a system receiving power of-17 dBm to-4dBm,which means that the Q value is 13.1dB.It shows that when the system performance is maintained at the best state,the stability of the receiver can be greatly improved by the nonlinear compensation of NDF.With the increase of the received power in the communication link,the improvement of the performance is very obvious.The second kind of optical nonlinear compensation technology is DPF nonlinear compensation based on the predistortion compensation.This technology mainly replaces the NDF with a two-period DPF based on the NDF nonlinear compensation link.The special dispersion management method of DPF is mainly used,which can not only reduce the total dispersion in the link,but also effectively inhibit the nonlinear effects such as self-phase modulation,cross-phase modulation,and four-wave mixing that seriously affect the link performance.By adding an optical nonlinear compensator of DPF,the Q value of the traditional link without dispersion compensation can be improved by 2.53 dB when the received power of the system is 0 dBm,and the stability of the receiver get a big boost when the link performance is maintained well.The two optical nonlinear compensation methods proposed in this paper can improve the performance of the 100 G PM-QPSK high-speed coherent optical communication system and have very important research significance.