Novel design proposal to minimize reflections in deep-ridge multimode interference couplers

We propose and demonstrate here the high efficiency of a novel design for deep-ridge multimode interference (MMI) couplers rendering them to behave like good transmitters with minimized reflections when integrated with emission devices. Using optical low-coherence reflectometry measurements, this novel design is shown to suppress to a great extent the highly detrimental internal resonance and often important backreflections inherent to even fully optimized deep-ridge MMIs.