Wavelength tunable all-polarization-maintaining fiber laser at 2 μm

In this paper, we present both wavelength tunable noise-like pulse (NLP) and continuous-wave (CW) generation in all-polarization-maintaining (all-PM) thulium-doped fiber lasers. By introducing a piece of polarization-maintaining fiber (PMF) whose birefringence changes with temperature in the all-PM thulium-doped fiber laser, a wavelength tunable range of 32.4 nm from 1910.4 nm to 1942.8 nm is realized in NLP regime, and a wavelength tunable range of 26.6 nm from 1937.7 nm to 1964.3 nm is realized in CW regime. The designed laser cavity is configured with all-PM fiber scheme and the special PMF is temperature-controlled, thus the laser owns high environmental stability and repeatability. To the best of our knowledge, this is the first report of wavelength tunable NLP output in the all-PM thulium-doped fiber laser.