Study On The Dispersion And Gain Flattening Of Fiber Raman Amplifier By TDM Pumping

With the development of society,modern communication networks are also rapidly developing?However,due to the rapid development of information,the use of erbium-doped fiber amplifier in traditional fiber-optic systems suffers from bottlenecks in the communication system's capacity such as nonlinear?fixed gain bandwidth?ripple of gain and optical surge,etc.Therefore,due to its amplification of super-wide bandwidth,fiber as the transmission medium,low noise figure,and available distributed amplification,fiber Raman amplifiers(FRAs)have become a solution to the above problems.However,fiber Raman amplifiers also have their limitations-gain ripple and dispersion.Therefore,it is necessary to further optimize the fiber Raman amplifiers in order to solve the problem of gain flatness and dispersion.To solve the problem of gain ripple,the spatial wavelength division multiplexing method is mainly used.FRA is pumping with different wavelengths at the same time.However,using this method will cause interaction between pumping light,nonlinear effects and four-wave mixing(FWM).Starting from the above points,this paper applies a method of time-division multiplexing(TDM)pumping FRA,which can effectively avoid the nonlinear effects and the FWM generated by the interaction between the pump sources.Due to the large non-linear effect and Amplified spontaneous emission(ASE)generated when the forward pump signal light is used,the backward pump signal light is used.In order to study the dispersion of TDM pumping FRA,the influence of different numbers of pumping sources and group velocity dispersion(GVD)on the signal light of TDM pumped FRA was studied with appropriate light pulses.We can get a good output pulse with appropriate wavelength and quantity of pumping source.When the transmission distance is short(the accumulation of fiber dispersion is small),the dispersion effect can be neglected.But when the transmission distance is long,appropriate GVD dispersion parameter fiber can obtain a better output pulse.The fourth-order dispersion compensation of TDM pumping FRA is further analyzed.The results show that choosing the proper initial parameter can extend the transmission distance of the optical pulse and increase the stability of the system.