MODELING AND PERFORMANCE ANALYSIS OF A FIBER BRAGG GRATING INTERROGATION SYSTEM USING AN ACOUSTOOPTIC TUNABLE FILTER

The performance of a fiber grating interrogation system using an acous to-optic tunable filter (AOTF) is analyzed, An equivalent linear circu it is presented to describe the system, which tracks the wavelength of a fiber Bragg grating (FBG) sensor in a FBG sensor array, From the mo del, the tracking resolution of a shot-noise-limited system has been d etermined for both transmissive and reflective interrogation of FBG's. An optimum ratio between the bandwidths of the FBG and the AOTF has b een derived. Experimental results of a tracking system are presented t o validate the theoretical predictions. The theory should also be suit able for interrogation systems using other forms of tunable bandpass f ilters for tracking the FBG wavelength.