Quantitative analysis of optical reflection in amultimode interference 3 dB coupler using a low-coherence interferometric reflectometer

Abstract
The quantitative reflection characteristics of multimode interference (MMI) couplers are investigated using a low-coherence interferometric reflectometer for the first time. MMI couplers are fabricated in an InP/InGaAsP/InP double-heterostructure, and the reflectivity from the interface between the MMI region and output waveguide is shown to be < –30 dB.