Abstract
A multi-wavelength fiber optic tunable laser is proposed for use in a fiber Bragg grating (FBG) vibration sensor array. The laser employs a semiconductor optical amplifier (SOA) as a gain medium, and FBGs as wavelength selection components. Since the SOA is an inhomogeneous broadening gain medium, stable multi-wavelength oscillation can be realized. In this configuration, oscillation outputs respectively serve as optical sources of the wavelength-division multiplexed (WDM) FBG sensor array in which multiple vibrations applied to the sensing FBGs can be detected at the same time. In addition, by controlling strain to the respective tuning FBGs the tunable operation can be achieved for the temperature compensation of the sensor outputs. For the demonstration of the performance principle of the sensor system, we have fabricated a dual-wavelength tunable laser and arranged two FBG vibration sensors in serial. In the experiment, the thermally stabilized WDM operation of the sensor array has been successfully demonstrated.
