Multipoint refractive index sensor for liquids based on optical fiber Bragg-gratings

A multipoint fiber optic refractive index sensor is presented, that is potentially capable of simultaneous measurement from many samples. The operation of this sensor is based on the reflection of light from a cleaved fiber end when the sensor is moved from one medium to another, while the sensor consists of two fiber couplers and an optical fiber Bragg grating (FBG). Experimental characterization of the sensor shows excellent agreement with numerical analysis and a precision of 0.002 and resolution of the order of 10-3. Through the use of multiple Bragg wavelengths measurement at multiple points is achieved.