Wavelength multiplexing of microelectromechanical system pressure and temperature sensors using fiber Bragg gratings and arrayed waveguide gratings

Abstract

Wavelength multiplexing of optically interrogated microelectromechanical system (MEMS) pressure and temperature sensors using both fiber Bragg gratings (FBGs) and arrayed waveguide gratings (AWGs) is demonstrated. The multiplexed sensor system using FBGs has the potential to multiplex about 70 sensors, depending on the FBG bandwidth and the one using AWGs has the potential to multiplex about eight sensors, depending on the number of AWG channels and the bandwidth of each channel. A dual-wavelength method incorporating a tunable laser is used to interrogate either the applied pressure or temperature experienced by the sensor, while a three-wavelength method can be used to simultaneously interrogate pressure and temperature. The Fabry-Perot cavity-based pressure sensors and temperature sensors are designed and fabricated using MEMS techniques. Experimental results, including response as a function of pressure or temperature, are characterized by good agreement between experimental and theoretical results. There is no observable crosstalk between the multiplexed sensors.