基于非对称脊波导的多种聚合物弯波导性能分析

Analysis on Performances of Several Polymer Bent Waveguide Based on Asymmetric Ridge Waveguide

以缩短马赫-曾德尔(M-Z)电光调制器分支波导为目的,将有机聚合物非对称结构的脊波导应用于S弯波导中。采用半矢量有限差分光束传输分析法,系统地分析了不同参数下采用非对称脊波导的三种常见弯波导,即正弦弯、圆弧弯和余弦弯分支波导的TM00光场传输损耗,并与采用对称脊波导的结构相比较。研究表明,在芯层厚度h=1.5μm、脊高为0.3μm、脊宽w=4μm、分支高度G=11μm的情况下,当脊波导短边芯层平板宽度s≥2μm时,在相同传输损耗条件下,正弦弯、圆弧弯和余弦弯分支波导长度分别可减少40%、30%和25%,该结果对有机聚合物M-Z调制器中分支波导的设计具有一定的参考价值。

In order to reduce length of the branch waveguide in Mach-Zehnder （M-Z） electro-optic modulator, the organic polymer ridge waveguide with asymmetric structure is applied in S-bend waveguide. Using the semi-vector finite-difference beam propagation method （FD-BPM）, the transition loss of TMo0 optical field is systematically studied in three conventional bend waveguides, namely sine-bend, arc-bend and cosine-bend, under different parameters, which is compared with the S-bend waveguide using symmetric ridge waveguide structure. The research results show that the lengths of sine, arc and cosine branch waveguides could be reduced by 40%, 30% and 25% respectively in the same transmission loss conditions, when the structure parameters are core height h = 1.5 μm, ridge width w = 4 μm, branch height G = 11 μm and ridge height is 0.3 μm, in the case of short core width s 2 μm. The results will have some reference value to the design of optical waveguide in M-Z modulator.