Gain Characteristic Of Two-Pump Fiber Optical Parametric Amplification Based On Micro-Structured Fibers

Fiber parametric amplification based on the four-wave mixing effect in optical fibers has attracted widespread attention due to its advantages of wide bandwidth,high gain,low noise and so on.Micro-structured fibers have controllable dispersion characteristics,no single mode cutoff characteristics and high nonlinearity,thus,the use of micro-structured fibers for two-pump fiber parametric amplification results in high peak gain and ultra-wideband gain bandwidth with short fiber lengths and low input pump power which can reduce system losses and make the structure of device simple and compact.Therefore,the two-pump fiber parametric amplification based on micro-structured fiber will have unique advantages for the optical communication system.This paper mainly includes the following aspects:Firstly,the nonlinear effect in the fiber is investigated,and the four-wave mixing principle and the optical-wave coupled equations in the fiber optical parametric amplification process are introduced in detail.The characteristics of the micro-structured fiber compared with conventional fiber are introduced.The finite element algorithm is used to establish the theoretical model of the micro-structured fiber.The dispersion curve is obtained based on the finite element theory.Then,the small-signal gain of fiber parametric amplification based on four-wave mixing is analyzed by numerical simulation method under one-pump and two-pump conditions.Secondly,the gain spectra and the saturation behavior of the two-pump fiber optical parametric amplifier in presence of random dispersion fluctuation as well as fourth-order dispersion coefficient β4 are investigated.The gain spectra of the two-pump FOPA is simulated by solving the coupled equations with fiber losses numerically,assuming the dispersion fluctuations along the fiber as a stochastic process with a given standard deviationσ and correlation length Lc.The gain performances of two-Pump FOPA are analyzed with the variation of Lc,σ and β4.The numerical analysis is significant for the research of two-Pump FOPA gain performance in the presence of dispersion fluctuation practically.Finally,a two-pump FOPA based on the micro-structure.d fibers in the telecommunication regio.n is investigated numerically.The fiber loss and pump depletion are considered.The influences of the fiber length,input signal power,input pump power and the center pump wavelength on the gain bandwidth,flatness and peak gain are discussed,which is also compared with the two-pump FOPA based on highly nonlinear fiber.The 6-wave model based analysis of two-pump FOPA is also achieved and compared with that based on the 4-wave model,further the gain properties of the FOPA based on the 6-wave model are optimized and investigated.Then,a two-pump fiber optical parametric amplifier(FOPA)based on the micro-structured fiber withAs2S3 background in the mid-infrared(MIR)region is investigated numerically.The genetic algorithms are to optimize the gain of the FOPA,and the amplifier peak gain,bandwidth and flatness are investigated in detail for a variety of the fiber length,the input signal and pump power.In addition,the comparison of the gain spectra between considering and neglecting the loss of the PCF is given and the effects of the fiber length and the pump power on the saturation gain are further investigated.