波导调制器的优化设计

Optimal Design of Optical Waveguide Modulator

利用傅里叶级数数值分析法对脊波导结构调制器进行了分析,特别针对SiO2缓冲层厚度不能忽略的情况,对其所造成的影响进行了计算。在此基础上得出了脊波导结构调制器中缓冲层厚度对特征阻抗和有效介电常数的影响特性。在综合考虑速度匹配、阻抗匹配、半波电压以及制作的困难程度等因素后,对调制器的各项参数进行了优化。结果表明,一定厚度的缓冲层能够在保持较大特征阻抗的同时,有效地降低等效折射率,大大地提高了调制带宽,迎合了更高速光纤通信的要求。

The waveguide modulator with a ridge structure is analyzed by using the Fast Fourier Traslator method. According to the fact that the thickness of the SiO2 buffer layer can not be ignored, the impact due to the thickness of the SiO2 buffer layer is especially calculated. On the basis of this calculation, the impact of the SiO2 buffer layer thickness on the characteristic impedance and dielectric constant in the modulator with a ridge structure is obtained. After considering the factors such as speed matching, impedance matching, half-wave voltage and difficulty in fabrication, all parameters of the modulator are optimized. The results have shown that the modulator with a proper thickness of buffer layer can effectively reduce its equivalent refractive index while keeping larger characteristic impedance, thus greatly improve its modulation width and meet the requirement of high speed fiber optical communication.