Feedback Stabilized Interrogation Technique for EFPI/FBG Hybrid Fiber-Optic Pressure and Temperature Sensors

This paper discusses a Single Wavelength Interrogation (SWI) technique used to measure fast changing pressure related signals and over a large operational temperature range. The novel technique is based on a fiber-optic pressure and temperature hybrid sensor, and a feedback stabilization technique for a tunable laser source. The fiber-optic hybrid sensor consists of a miniature diaphragm based all-silica Extrinsic Fabry-Perot Interferometric (EFPI) Fiber-Optic Pressure Sensor (FOPS) which additionally incorporates a Fiber Bragg Grating (FBG) temperature sensor. The FBG temperature sensor is used as a feedback element to stabilize the output wavelength of the tunable laser source to operate always in the linear range of the EFPI FOPS.