Modal pattern analysis and experimental investigation of multimode interferometric sensing: a path to fully-integrated silicon-CMOS-based chem/bio sensors

A multimode, Mach-Zehnder, chem/bio sensor with sensitivity developed through modal pattern analysis is demonstrated on silicon. Simulated and experimental data show that waveguide structures less than 5000-/spl mu/m enable fully-integrated sensors with index sensitivities near 3/spl times/10/sup -6/ and methanol-in-vapor sensitivities near 250 parts-per-billion vapor (ppbv).