Optimization Of The Performance Of Fiber Optical Parametric Amplifier

With the rapid development of DWDM technology in optical fiber communication,performance of erbium-doped fiber amplifier which has been used in a large scale can not meet the needs of optical communications,So a comprehensive fiber amplifiers,as well as capable of simultaneously amplifying multiple signals is in need urgently.In recent years,technology based on the nonlinear phenomena in optical fiber has become highlight in research,such as optical fiber Ramanamplifier,Raman amplifier not only has a wide gain bandwidth,but also enables online amplification,thus it has been widely used.However,optical fiber Raman amplification requires a high pump power,and the gain is not significant enough.When fiber optical parametric amplification based on the nonlinear effect in optical fiber-four-wave mixing has the advantage of high-gain,high bandwidth and low noise,and has the ability to provide a flat and high broadband for signals at arbitrary wavelength as well.In this background,further research about complex parametric amplification as to give full play to the potential of parametric amplification is very important to the development of optical communication,DWDM technical requires optical amplifiers have the same gain for multi-channel signals,which requires optical amplifiers having a flat gain spectrum.This paper first studies the performance of cascade optical fiber parametric amplification,then optimizes differential evolution algorithm.Based on the analysis of the optimizing results,the differential evolution algorithm is in the presence of defects such as easy to fall into local optimum convergence and speed instability,thereby the paper introduces chaotic maps into the differential evolution algorithm,since the chaotic map has the nature of ergodicity,randomness and regularity[11],so as to strengthen the ability of local search algorithm,and it is possible to avoid local optimal solution,so In this paper,the gain spectrum of cascade parametric amplification is further optimized by the chaotic differential evolution algorithm with a better performance.The main results are as follows:(1)Derive and analyze the parametric amplification coupled mode equations both in analytical solutions and numerical solution.And study the performance of gain spectrum of both single and double-pumped parametric amplification by simulation,explore the different characteristics of the model between analytical solutions and numerical solution when simulation.Studies the parameters which have effects on parametric amplification,such as pump wavelength,pump power,fiber zero-dispersion wavelength and fiber nonlinear coefficient.(2)It is explored by simulation in the case of both narrow-pitch and wide-pitch double-pumped parametric amplification how the zero-dispersion wavelength affect the performance of the gain.The conclusion is drawed that for a wide double-pumped parametric amplification,gain performance is susceptible to fluctuations of the zero dispersion wavelength,which lay a foundation for the following research.(3)Based on the fact that the fiber structure,temperature and some other factors can affect the zero-dispersion wavelength,in this paper the idea of a temperature control system to control the parametric gain is suggested,the performance of the parametric amplification is controlled by adjusting the value of the temperature,which will absolutely change the value of the zero-dispersion wavelength.(4)Introduce the principle of the intelligent optimization algorithms used in the paper-differential evolution algorithm,then use it in optimization of the performance of cascade fiber optical parametric amplification.The specific optimization methods and processes are explored,and in the process of simulation I get a gain spectrum whose bandwidth approaching 400nm,gain is 16dB,and the fluctuation is only 0.9dB,which prove that differential evolution algorithm can be used to optimize FOPA to get a more flat parametric gain spectrum.(5)The optimization results above shows that the differential evolution algorithm have some defects.So an improved differential evolution algorithm-Chaos differential evolution algorithm is introduced for further optimization of the cascade fiber optical parametric amplification,Chaos differential evolution algorithm have the ability of overcoming the trend to fall into the global optimum,as well as the shortcoming of convergence rate instability,and a better result of optimization has been got.