光纤中瞬态受激布里渊与瑞利后向散射的协作效应

Cooperative Effect of Instantaneous Stimulated Brillouin and Rayleigh Backscattering in Fiber

光纤中的非线性效应极大地影响了光信号的传输距离和保真度.通常情况下,光纤中的非线性效应主要是受激布里渊散射(SBS)和瑞利散射.避免或者合理利用这些效应是解决上述问题的可能途径.实验研究了瞬态情况下具有光纤相位共轭镜的主振荡器-功率放大器(MOPA)系统在不同重复频率和泵浦能量下的输出光谱特性.结果显示:在适当的泵浦、耦合条件下,多模光纤也能单模工作.对于所观察到的谱线变窄现象解释为受激布里渊散射与Stokes场的双瑞利散射造成的分布式动力学反馈的协同作用.

Nonlinear optics effect will decrease hugely transmitting distance and fidelity of optical signal in fiber. Stimulated Brillouin scattering （SBS） and Rayleigh scattering are main nonlinear effects in fiber. To avoid or make good use of these effects may solve questions mentioned above. It is experimental investigated that Stokes spectrum characteristic under different repetition rate and pump energy in master-oscillator-power-amplifier （MO- PA） system with phase-conjugation mirror. It is showed that multi-mode fiber can work like single-mode fiber under condition of opportune pumping and coupling. The phenomenon of narrowing spectrum is explained as the result of cooperative action of stimulated Brillouin scattering and dynamic distributed feedback that is due to double Rayleigh scattering of the Stokes field.