光隔离器法抑制Michelson干涉型光纤水听器中的SBS

光纤水听器是利用光的干涉信号进行探测的，但随着入射光功率的增加，易发生受激布里渊散射（stimulated Brillouin scattering，SBS）效应，并因而产生噪声，限制入射光功率的增加，极大地影响探测信号。为了抑制SBS效应，提高光纤水听器性能，以Michelson型光纤水听器为例，从实验和理论上研究了SBS及其阈值特性。根据阈值公式分析了提高阈值的方法，着重讨论了光隔离器法对SBS的抑制。最后利用时域有限差分方法对光纤内的入射光、Stokes光和声波的时空分布进行了分析。只要给出初始条件及光纤参数即可得出光纤内各波的时空分布。通过开展抑制此效应的研究，不仅为可调谐相干光的产生提供一个新途径,而且可作为一种有效手段来研究各种光纤系统中的散射特性。

Suppression of SBS in fiber hydrophone by optical isolators based on Michelson fiber interferometer

The fiber hydrophone utilizes the interferential optical signal to detect. The effect of the stimulated Brillouin scattering (SBS) occurs with the increase of the optical power, which makes noise, limits the incident light power and affects the detecting signal seriously. For suppressing the SBS to improve the characteristic of fiber hydrophones, research, based on the Michelson fiber hydrophone, was done, and the methods of increasing the threshold, especially the method of using the optical isolator were investigated according to the threshold equation. The time-space distribution of incident light, Stokes light and sound wave in the fiber is analyzed with FDTD. The time-space distribution of each wave in the fiber can be obtained so long as the initial condition and fiber parameters are given. The research on suppressing this effecting can offer a new way to produce the tunable coherent light, and it can be an effective method to study the characteristic of different scatterings in fiber system.