EDF-Based Edge-Filter Interrogation Scheme for FBG Sensors

A fiber Bragg grating (FBG) sensor employing an interrogation scheme based on erbium-doped fiber (EDF) edge detection filter, with enhanced detection bandwidth and intrinsic temperature insensitivity, is proposed and experimentally demonstrated. The edge filter is based on the spectral dependence of absorption in EDF with the possibility of tailoring the absorption profile using appropriate lengths of EDF. A wide filter bandwidth of about 10 nm and a slope detection sensitivity of 1.0 dB/nm in the C-band is demonstrated and validated by simulation results. The proposed scheme is versatile and allows for simultaneous interrogation of multiple FBGs.