Multi-Wavelength Tunable Fiber Laser using SOA: Application to Fiber Bragg Grating Vibration Sensor Array

A novel multi-wavelength fiber ring laser is proposed in order to construct a thermally stabilized fiber Bragg grating (FBG) vibration sensor array in which detection of multipoint vibrations and temperature compensation of the detection can be achieved. 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 at the Bragg wavelengths of the FBGs used. The oscillation output from the laser is used for an optical source of wavelength division multiplexed (WDM) FBG vibration sensor array, in which each wavelength component of the output provides one of the optical sources for arrayed FBG vibration sensors. In addition, the wavelength of the laser source can be tuned by applying strain to the FBGs of the laser. The detection scheme of the FBG sensors is based on intensity modulation technique and the thermal stabilization is realized by the wavelength tuning of the laser. In the experiment, a dual-wavelength tunable fiber laser has been fabricated and fundamental characteristics of the laser have been investigated. By applying the laser to the FBG sensor array, simultaneous two-point vibration detection and temperature compensation of the detection have been also demonstrated.