We demonstrated an all-fiber single-frequency DBR master oscillator and power amplifier at 1992.6 nm. The maximum output power of the fiber amplifier was 100 W with a slope efficiency of 53% and the optical signal-to-noise ratio was about 50dB. The linewidth was less than 66 kHz and the beam quality factor M<sup>2</sup> was 1.22 at the maximum output power. The RINs of the seed and the power amplifier were measured to be -120 dB/Hz and -102 dB/Hz at the relaxation oscillation frequency, respectively.
Frequency swept laser sources have various applications, such as LIDAR, spectroscopy, sensing. We demonstrate a 1.5-μm frequency-sweepable single frequency fiber laser in this work. By modulating the intensity of the pump, photo-induced refractive index change occurs in the gain fiber and the free spectral range of the laser is improved. As a result, the frequency sweeping can be realized. The DBR structure is employed to ensure the single-frequency operation. The central wavelength and the maximum sweeping range is measured to be 1550.25nm and 800MHz, respectively. A repetition rate up to 1kHz with an average output power of 0.6mw is realized.