综述了近年来光纤中声光耦合的研究及其一些应用。由PZT产生的弹性声波在光纤上传播，导致光纤周期性的微弯，引起光纤内模式耦合。其作用类似于长周期光栅，但又因为声波的频率、振幅随着施加的RF信号的频率和振幅的改变而改变，因而相对长周期光栅来讲有着灵活、可调的优点。根据声波对光纤共振波长的调谐特性，可以做出很多性能优异的光器件，如频移器，窄带和超宽带的可调滤波器，可调光衰减器，光开关等。

The research and application of acousto-optic mode coupling in fibers is summarized here. The flexural acoustic wave generated by PZT propagates along the fiber, and creates periodic micro-bends, introducing a periodic refractive-index perturbation along the fiber which induced mode coupling. This effect is similar to the LPFG, but it is more excellent than LPFG because the frequency and amplitude of acoustic wave can be tuned by the frequency and amplitude of RF signal. According to the characteristic of tunable, we can achieve many excellent optical devices, such as frequency shifter, narrowband and broadband acousto-optic tunable filter, variable optical attenuator, optical switch and so on.