Widely tunable multi-wavelength thulium-doped fiber laser based on nonlinear polarization rotation

A kind of widely tunable multi-wavelength thulium-doped fiber laser based on nonlinear polarization rotation (NPR) is achieved. Using a ring cavity, 1565 nm laser pump, a 3m long thulium doped fiber, and NPR effect is used as filter. By adjusting the fiber polarization controller, stable 1-5 wavelengths laser output is observed at room temperature, and the side mode suppression ratio is 40-60 dB. The measured results show that the wavelength shift is less than 0.2 nm within one hour and the output peak power fluctuation is less than +/- 3 dB. The wavelength spacing is about 6.75 nm and the tuning range is 33 nm. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1540-1543, 2016