具有单一复合调制区的多模干涉效应耦合器1×3光开关的分析

基于多模干涉自映像原理，分析了一种仅含一个复合调制区的1×3光开关。该开关处于不同工作状态时，调制臂上所加相位调制量之间存在倍数关系，于是可将调制臂上的相移器组合成一个复合调制区，通过连续改变复合调制区的折射率变化量，因此可以将来自任一输入端的光场轮流切换到任意输出端口。以Al0.07，Ga0.93As／GaAs脊形波导结构为例，采用BEAMPROP软件，对该开关进行了优化和理论验证。消光比高达30．3dB；相邻通道之间的串扰低于-29．8dB；在1．31μm工作波长处约50nin的波谱范围内，串扰低于-20dB。该结构可简化传统多通道开关的调制方法，降低外加控制方法的复杂程度。

Analysis on Multimode Interference Coupler-Based 1×3 Optical Switch with Mono-Compound Modulation Region

By employing the self-imaging properties of multimode interference, a 1×3 optical switch with mono-compound modulation region is presented. When at different switching states, a multiple relation exists in the acquired modulation magnitudes in the connecting arms, and therefore, the phase shifters in the arms can compose a mono-compound modulation region (MCMR). By contimuously changing the refractive indices in the MCMR, light incident from any input port can be switched alternatively to arbitrary output port. Based on Al0.07Ga0.93As/GaAs ridge structure, the proposed device was optimized and theoretically demonstrated by employing BEAMPROP software. The extinction ratio is as high as 30.3 dB. The crosstalk between adjacent channels is less than -29.8 dB. In a wide spectral range (～50 nm) around 1.31 μm wavelength, the crosstalk keeps lower than -20 dB. This device may greatly simplify the modulating scheme of traditionaly multichannel switch and relax the complextity of external controlling.