共线声光模式转换效率的分析与计算

Analysis and numerical calculation of mode conversion efficiency in collinear acoustooptic interaction

利用声表面波共线声光效应的衍射光栅可使波导中导模向泄漏模转换 ,此现象在光通信在线解复用系统具有潜在应用前景。利用耦合模理论求解这一过程 ,模式转换效率可以化作声波频率、声光作用长度、波导厚度和声波功率密度的函数 ,利用数值计算得出结果并给出其关系。由数值计算结果可知 ,x切质子交换铌酸锂波导模式转换效率最大 ,适当选择波导长度和声驱动功率密度 ,其TE0 →TMυ 转换效率可达 90 %以上。

The guided to leaky mode conversion with the induced diffraction grating from the collinear surface acoustic wave (SAW) possess potential application in onboard optical demultiplexing of optic communication systems. This phenomenon is analyzed using the coupled mode theory. Mode conversion efficiency has been calculated as functions of acoustic frequency,interaction length,guiding layer thickness,and acoustic drive power density. It is shown that the x cut configuration features the highest mode conversion efficiency,measured mode conversion efficiency as high as 90% is obtained at the relevant acoustic drive power density and interaction length.