Theoretical Study On Stimulated Raman Laser Based On Fluoride Fiber

Stimulated Raman scattering?SRS?effect is a very important nonlinear effect in nonlinear optical fiber optics.And fluoride fiber has been widely studied for its numerous excellent nonlinear properties.With the help of the split-step Fourier method?SSFM?,the output characteristics of the first-order Raman fiber laser?RFL?and the second-order cascaded Raman fiber laser based on fluoride fiber are investigated in the paper.The fiber lasers are pumped by the fiber laser at 1.55?m.The optimization on simulation results is conducted.This work provides theoretical guidance for the designing the SRS fiber laser at1.7-1.9?m waveband based on fluoride fiber with excellent output properties.The main contents of the work are as follows:1.Using the SSFM,the influences of the output reflectivity,launched pump power and fiber length on laser performance of the first-order RFL are investigated.The simulation results indicate that the optimal fiber length ranges from 5 to 10 m under the condition that the output reflectivity is 10%and the pump peak power is 2500 W.2.Using the SSFM,the influences of the output reflectivity,launched pump power and fiber length on laser performance of the first-order RFL are investigated.The optimized results are given,too.The simulation results indicate that the optimal fiber length ranges from 10 to 15 m under the condition that the output reflectivity is 10%and the pump peak power is 3000 W.After optimization,the maximum output of33.782 W and the highest optical conversion efficiency of 68.2%are obtained.In addition,the influences of R₁^B,the reflectivity of FBG12,are also studied.The simulation results indicate that with the increasing of R₁^B,the pump threshold power of the laser gets smaller and smaller.3.Pumping the laser with the fiber laser having different pump wavelengths,the analysis on center wavelength tuning is carried on,which demonstrates that designing the wavelength tunable pulsed RFL at 1.7-1.9?m waveband based on fluoride fiber is realizable theoretically.