采用有限差分光束传输法(FDBPM)分析光波在大角度交叉区域的传输过程,利用padé近似解决大角度传输问题;利用透明边界条件弥补边界光波反射现象,通过追赶法编程计算有限差分方程组,得到在一定光波导结构条件下传输损耗与交叉角度之间的关系。在此基础上,利用低压化学气相沉积技术在硅衬底上制作了二氧化硅交叉波导结构,实验结果表明有限差分光束传输法在分析大角度交叉时具有比较高的计算精度。

The characteristic of the light propagation across the wide angle crossed waveguide is analyzed using the finite difference beam propagation method (FDBPM). Padé approximation is used to deal with the wide angle problem and the transparent boundary condition is used to deal with the optical reflection at the boundary. Through calculating the finite difference equations using the pursue after method, the relationship between the propagation loss and the intersection angle has been obtained. On this basis, the crossed silica waveguides are fabricated on silicon substrate by low pressure chemical vapor deposition method. Experiments show that the presented FDBPM has good accuracy and can be used to analyze wide angle crossed waveguides.