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

ABSTRACT 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. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1540–1543, 2016