提出了一种利用自准直效应基于TM模式二维光子晶体的1×5光分束器。该结构由两个环形谐振腔级联而成,每个环形谐振腔有4个可改变介质柱半径的分光镜。首先运用多光束干涉原理分析光分束器中各个端口的透射谱,按照设置的比例对8个分光镜进行合适的组合,自准直光束即可从5个出口出射,达到1×5分束器的效果;然后利用时域有限差分软件方法来对数值进行模拟,其结果和理论值吻合地较好。该结构尺寸较小,自由光谱范围大,在未来的高密度集成光路中会有较好的应用前景。

In this paper, the 1×5 optical splitters (OSs) based on 2D rod-type silicon photonic crystal embed cascaded self-collimation (SC) ring resonators (CSCRR) is proposed. The 1×5 OSs consist of eight beam splitters, which are formed by varying the radii of the rod. With self-collimation effect, we can manipulate the lights propagation in the OSs. Here we consider TM modes. Utilizing multiple-beam interference theory, the theoretical transmission spectra at different outputs are analysed. These transmission spectra can help us to set the radii of eight slitters properly, for we can control the light coming out from five ports with the light-intensity ratio we need. Meanwhile these outputs transmission spectra are investigated by the finite-difference time-domain (FDTD) method. The simulative results have an agreement with the theoretical prediction. The 1×5 OSs will have practical applications in photonic integrated circuits.