Compact two-mode (de)multiplexer based on MMI couplers with different core thickness on InP

摘要

A novel design of two-mode (DE)MUX based on multimode interference (MMI) couplers on InP substrate is proposed. A phase shifting section based on the thickness variation of the core layer is introduced in the (DE)MUX to realize a 100% mode conversion efficiency and multiplexing. The total length of the structure is only 549 μm, much shorter than other InP based mode (DE)MUXs. Simulations show that, the device crosstalk is below -20 dB and the insertion loss is lower than 1 dB for both of the fundamental mode and the first order mode within the whole C band. This new structure can be potentially integrated with other devices based on InP substrate to serve as a monolithic few-mode transmitter/receiver.