针对半导体光波导实际制作过程中出现的典型工艺缺陷,基于有限元法提出了有效的分析方法。首次计算了真实光场入射情况下,缺陷存在时波导内部的光场,并分析了缺陷位置、大小、缺陷类型和入射光波长对半导体光波导损耗和模式耦合的影响。分析结果表明,波导传输损耗随缺陷大小和光波长振荡变化;折射率较大的缺陷,振荡频率较高;缺陷从芯区中心移向边缘时,传输损耗随波导结构尺寸振荡变化,变为单调增大。损耗能量一部分形成辐射模进入衬底,另一部分耦合成高阶模。缺陷明显增加半导体光波导损耗,改变波导传输模式,显著劣化集成光路性能。
For the typical process defects of semiconductor optical waveguide in the actual fabrication process,an effective analysis method is proposed based on the finite element method. For actual incident optical fields, theoptical fields in waveguide are calculated for the first time when the defects exist. The effects of the defect position,size, type and wavelength of the incident light on the loss and mode coupling of semiconductor optical waveguideare analyzed. The results show that the waveguide transmission loss oscillates with defect size and light wavelength.The defect refractive index is larger, oscillation frequency is higher. When defects are moving from the core centerto the edge, the oscillation of the transmission loss with waveguide structure size become monotone increasing. Onepart of the loss energy becomes the substrate radiation mode, and the other is coupled to high-order modes. The pro-cess defects make semiconductor optical waveguide loss increase greatly, the waveguide transmission mode ischanged, and the integrated optical circuit performance is degraded significantly.