An optomechanical pressure sensor using multimode interference couplers

Abstract

A new optomechanical pressure sensor using multimode interference (MMI) couplers and a thin p(+)-Si membrane is presented. We simulate the device characteristics by the normal mode theory considering deflection and strain of the membrane. The optical waveguide is made of a single-mode, strip-loaded SiO2-SiNx-SiO2 system. Device size can be reduced to 0.5 x 13 mm(2) by using a MMI coupler, and the total thickness of the membrane is 5.9 mu m. The measured sensitivity is 11.98 ppm/Pa in a range of 50 kPa, which is larger than that of conventional capacitive sensors.