声光可调谐滤波器多波长同时滤波的特性

集成光学声光可调谐滤波器 (AOTF)有很多优点 ,特别是它可以同时滤出多个波长 ,因此在波分复用(WDM)光纤通信网络中有重要应用。针对其这种特性 ,运用耦合模理论 ,导出了同时存在两束声波时的严格的耦合模方程。在此基础上 ,得到滤波特性的数值解 ,分析了多波长同时运用时 ,滤波器的主峰强度、中心波长和 3dB带宽随时间的波动 ,同时也分析了当信道间隔较小时滤波特性失真严重、噪声较高的原因。在分析了共线型声光可调谐滤波器多波长同时运用所存在缺点的基础上 ,提出利用准共线模转换器来改善声光可调谐滤波器多波长同时运用的性能。

Characteristics of Multiwavelength Operation of Integrated Acousto-Optical Tunable Filter

Integrated acousto optical tunable filters (AOTF) have potential application in WDM optical networks because of some advanced properties, especially, the unique property of simultaneous multiwavelength filtering. The exact coupling equations with two acoustic waves travelling simultaneously were derived. Based on the coupling equations, some numerical results of conversion characteristics are given and the fluctuation of the main peak, the center wavelength and the FWHM (full width of half maximum) are analyzed with respect to time. The reasons for serious distortion and the higher crosstalk for narrower channel sapcings are discussed. Considering the drawbacks of the collinear integrated acousto optical tunable filter in multiwavelength operation, use of quasi collinear acousto optical mode converter for improving the conversion characteristics of AOTF is proposed.