High Precision, Low-Cost Interrogation System for Fiber Bragg Grating Sensors

For various applications Fiber Bragg Gratings (FBG) have emerged as excellent sensor elements for parameters such as strain and temperature. FBG's have a periodic modulation of the refractive index along the fiber axis and reflect light at a certain wavelength, the so called Bragg-wavelength. In a FBG sensor element strain and/or temperature variations are transformed to a shift of its Bragg-wavelength. In this study a FBG interrogation system is presented that is optimized with regard to robustness, low-cost and high precision. The system is based on a piezo driven tunable fiber Bragg grating as an analyzing element and includes a wavelength stabilization scheme.