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. They are designed not only to output a certain fraction of the input power. 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. Multimode interference (MMI) devices are a cornerstone in the field of integrated optics, offering efficient and innovative solutions for managing light in. Why Integrated Photonics? Why Multimode Interference Waveguides?.