A Novel Mode Multiplexer/Demultiplexer for Multi-Core Fibers

In this letter, a mode multiplexer/demultiplexer (MUX/DEMUX) for multi-core fibers (MCFs) based on multimode interference (MMI) effect is proposed. Due to the coincidence of the rows of the transfer matrix of an MMI coupler and the modal profile of the MCFs with linearly aligned cores, an MMI coupler with the aid of a phase shifter array is able to distinguish different super-modes of the MCFs. The output port number indicates the number of the super-modes inside the MCFs. Detailed theoretical derivations and numerical simulations are provided to demonstrate the multiplexing/demultiplexing capability of the device. The proposed mode MUX/DEMUX can be fiber based or waveguide based and is easy to be integrated with the fiber system.