Method and system for interrogating an optical fiber sensor of the fiber bragg grating type, using a tunable optical bandpass filter

Abstract

A method for interrogating an FBG sensor includes lighting the FBG sensor with a broadband excitation optical radiation, conveying the optical spectrum transmitted or reflected by the FBG sensor to a tunable optical BPF having a first extraction port and a second transmission port, tuning the optical BPF at a constant operating wavelength, depending on nominal operating wavelength of the FBG sensor, detecting a first optical signal exiting the first extraction port, converting, by a first opto-electronic receiver, the first optical signal into a first electrical signal, representative of a wavelength shift of the spectrum transmitted or reflected by the FBG sensor, detecting a second optical signal exiting the second transmission port, converting the second optical signal, by a second opto-electronic receiver, into a second electrical signal, representative of an optical reference power, and determining the wavelength shift of the spectrum transmitted or reflected by FBG sensor, based on detected first and second electrical signals. A system for interrogating an FBG sensor is also provided.