Taylor series expansion method for TM mode of polymer waveguide M-Z modulator

Mach-Zehnder waveguide is an important part in integrated optics.The transverse distribution of refractive index of polymeric ridge waveguide was calculated with the effective index method(EIM) and 3-D propagation was converted into 2-D propagation according to the structural characteristics of the polymeric ridge waveguide.Based on para-axial scalar equation,using Crank-Nicholson scheme,the basic calculation scheme of Taylor series expansion method was obtained and optimized.By simulating the TM mode of a real Mach-Zehnder waveguide,the influence of various parameters on the loss was analyzed.The results show that this method is accurate,stable and easy to program.