Design, BPM simulation and optimization of Mach-Zehnder 3-wavelength demultiplexer based on Runge-Kutta method

The design, BPM simulation and optimization of a Mach-Zehnder 3-wavelength demultiplexer (MZ-3WDM) for the wavelengths λ1=980 nm, λ2=1310 nm and λ3=1550 nm based on the Runge-Kutta method is presented. The combination of the effective index method based Rung-Kutta and a finite difference vector beam propagation method (FD-VBPM) provide for a computational design tool that yields good accuracy. The total device length obtained is 1.49 cm. The average distinction ratios, for the three wavelengths, 980 nm, 1310 nm and 1550 nm obtained are 34, 32 and 26 dB, respectively. The effect of the wavelength deviations, the error in diffusion time and the error in the waveguides width on the extinction ratio were carried out. The results of the study indicated that a 20 dB of extinction ratio for the three wavelengths could be obtained over a bandwidth of 32 nm range, a ±12 min error in diffusion time and a ±100 nm error in waveguides width