Wavelength-switchable fiber laser for thermally stabilized fiber Bragg grating vibration sensor array

A novel erbium-doped fiber laser (EDFL) has been proposed to implement an optical source of a fiber Bragg grating (FBG) vibration sensor array based on intensity modulation technique. The laser consists of an erbium-doped fiber amplifier (EDFA), an optical coupler and an optical switch with tuning FBGs, in which the lasing wavelength is determined by the Bragg wavelength of the selected timing FBG to serve as an optical source of one of the arrayed FBG sensors. In addition, the temperature effects on the sensor outputs due to environmental temperature can be compensated when the temperature changes are applied commonly to both the tuning and sensing FBGs. In the experiment, multipoint vibration detection with a temperature-insensitive operation is successfully demonstrated by constructing two sensor elements arranged in tandem.