Silicon-nanowire-based optical sensor with high sensitivity and large measurement range by using Mach-Zehnder interferometer-coupled microring

Abstract

A Mach-Zehnder interferometer-coupled microring is experimentally demonstrated for optical sensing with a high sensitivity (~111 nm /RIU), a high extinction ratio (>26dB), and a very large quasi free-spectral-range (>100 nm), which helps to obtain a large measurement range. The MZI-coupled microring sensor still has good performance when the reflective index of the ambient materials largely changes (1