Simulation and Modelization of Multimode Interference Demultiplexer by using BPM Method

Optical switches based on planar lightwave technology offer stable and robust means of achieving space- division switching. One form of integrated switch that shows some promise is the generalized Mach-Zehnder optical switch. This switch normally comprises two multimode interference (MMI) couplers connected by an array of phase shiffers. We show through detailed simulations that the length of conventionally designed multimode-interference couplers. A 1310 and 1550 nm coarse wavelength multi/demultiplexer based on polymer is demonstrated for the first time. The device is designed based on a combination of general interference and paired interference mechanisms of multimode interference (MMI). Short tuning of the device makes it possible to fabricate MMI coupler with larger free spectral range, significantly increases the 3-dB bandwidth for the total transmittance. By the structure improvement by S-curve we increase the normalized output power of the field for A=1310 nm from 0.8 to 0.95.