镀膜光纤声光相位调制器频率响应特性的研究

Research into the characteristics of the frequency response of the optic fiber phase modulator with piezoelectric ZnO coating

本文对光纤声光相位调制器 (OF -AOPM)的频率特性进行研究。分析了OF -AOPM的调相原理 ,研究结果表明 :在调制频率远离氧化锌压电薄膜的半波谐振频率的时候 ,光相位的调制不仅依靠径向应力 ,同时还依靠轴向应力。通过同时考虑径向和轴向应力的变化 ,得出了OF -AOPM在整个频率域范围内的响应特性。

An exact theory for an optical acousto - optic phase modulator with a ZnO coating （OF- AOPM） has been developed, which is made by considering only the radial strain induced by acoustic wave in the resonator. It has been shown that radial strain alone gives strong modulation in the vicinity of a modulating frequency close to half- wave resonance of the Piezoelectric ZnO Coating. At frequency far from this region, not only radial strain but also axial strain may be counted on for optical modulation. In this paper, phase modulation in OFPM for the entire frequency region is presented by considering beth axial and radial strains. The theoretical calculation shows good agreement with the experimental results.