Design and analysis of low loss MMI based 4??4 optical switch using Benes architecture with SOAs

摘要

This paper presents an overview of self-imaging principle used in MMI couplers and also explains the application of multimode waveguide as an optical switch. The application of MMI coupler to realize a 2??2 optical switch has been explained by varying the refractive indices of various regions of MMI section by only 1-2% and the switch is found to exhibit 2-10% loss for various coupling states at different power inputs. Then the basic 2??2 switch is exploited in design of 4??4 benes switch. Benes switch is used as it is suitable for large switches requiring fewer SOAs which make it a good candidate for further use in higher order switches. Simulation results are shown. Power coupling losses occurring in 4??4 switch are compensated using minimum number of SOAs with low input injection current of the order of 10-20mA.