Wavelength tunable Q-switched fiber laser using fiber Bragg gratings

This is paper reports on a Q-switched Er-doped fiber laser using the stress dependence of a wavelength of reflected light from fiber Bragg gratings. The laser cavity consists of a 0.5-m-long Er-doped fiber and two fiber gratings (FG) attached at both ends of the fiber. The pump laser is a 1.48 μm semiconductor laser. Wavelength control of the reflected light from the FG was carried out by bending a metal rod to which the FGs were attached, or by applying stress to the FG using a piezoelectric transducer (PZT). Q-switching was carried out by changing the wavelength of the reflected light at high speed using the PZT. When the pump power was 26 mW and the repetition rate was 1 kHz, the optical pulse had a pulse width of 2.46 μs and a peak power of 2.1 mW. By adjusting the reflection from the FG, the oscillation wavelength was varied by 4 nm. The relationship among the reflection spectrum of the FG, the wavelength shift of the reflected light from the FG, the pump power, and the pulse width of the optical pulse was clarified.