Monolithic optical interferometers for MEMS applications

We discuss two monolithically integrated interferometric sensor systems of interest for MEMS applications. The first is an optical displacement measurement microsystem on a chip; this system consists of a Michelson interferometer with an integrated DBR laser, waveguide photodetector and phase modulators. The second is configured as a Mach-Zehnder interferometer and is used for high-resolution refractometry with applications in biological and chemical sensing. Both of these sensor photonic integrated circuits employ the same optical and optoelectronic devices and share closely related fabrication technologies. The integrated interferometers were based on a GaAs/AlGaAs double heterostructure laser substrate, with one or more quantum wells in the active region.