Calculate the broadband transmission and optical loss through a 1×2 port multi-mode interference (MMI) coupler. Use the device S-parameters to create a compact model of the MMI in INTERCONNECT. First, the fundamental mode of the input single-mode waveguide is calculated and used as input for the beam propagation. A multi-mode interferometer (MMI), also known as a multimode interference coupler, is a micro-scale structure in which light waves can travel, such that the optical power is split or combined in a predictable way. In an MMI, light is confined and guided, and thus the MMI is essentially a broad. plers based on Self Imaging.