Widely tunable continuous-wave fiber laser in the 1.55-1.8  µm wavelength region

In this paper, we experimentally demonstrate a continuous-wave widely wavelength-tunable fiber laser based on erbium- and bismuth-doped fibers in parallel configuration. A diffraction grating was used for wavelength tuning, and the tuning range of 268 nm (from 1545 to 1813 nm) was obtained using Littrow design. This result is significantly greater than demonstrated previously in the same spectral region with erbium or bismuth doped fiber lasers.