组合光纤中受激拉曼散射和四波混频研究

在抽运光和耦合条件不变的情况下，研究了熔接组合的非零色散位移单模光纤(NZDSF)和标准单模光纤(SMF)中的受激拉曼散射(SRS)和四波混频(FWM)产生和传输特征。采用532 nm脉冲激光抽运NZDSF，从20 m处开始产生以LP₀₁模传输的SRS第一级Stokes光;紧接着在30 m处产生了FWM，SRS受到FWM抑制，传输模式逐渐转化为LP₁₁模;经过80 m处熔接点后，由于熔接处双锥光纤结构使光场模式互相干涉，光波模式恢复为LP₀₁模，FWM受到抑制。该现象和机理有利于抑制密集波分复用(DWDM)系统中光学非线性失真和促进光孤子通信系统的发展。

Study of Stimulated Raman Scattering and Four Wave Mixing in an Optical Fiber Combination

In the present paper, yielding and propagation characteristics of the stimulated Raman scattering(SRS) and four wave mixing(FWM) were researched in a non-zero dispersion shifted single-mode optical fiber(NZDSF) and standard single-mode optical fiber(SMF) combination under the same pump light and coupling conditions. At 20 m length of NZDSF, The first order Stokes 544.6 nm of SRS gains and is transported by LP₀₁ mode. At 30 m length, 537.7 nm of FWM emerges but 544.6 nm of SRS decreases whose mode is gradually transformed into the LP₁₁ mode. After 80 m length of NZDSF, because the splice point between NZDSF and SMF is a biconical fused taper and their transmission mode interferes with each other, FWM is suppressed and the mode is converted to LP₀₁ again. The phenomena and mechanisms are conducive to inhibiting of optical nonlinear distortion in a dense wavelength division multiplexing system and to developing optical soliton communication system.