Tunable Dual-Wavelength Laser at 1.8 μm Based on SESAM and NOLM

Dual-wavelength lasers achieved in a single cavity at slightly different repetition rates are widely used for optical sensing, optical spectroscopy and dense-wavelength-division-multiplexing. Various methods like Lyot filter, fiber taper, nonlinear polarization rotation, nonlinear optical loop mirror (NOLM) and nonlinear amplified loop mirror have been used to form a comb filter for dual-wavelength pulse generation, especially at 1.0, 1.5 and 2.0 μm wavelengths [1]. Here, we present a tunable dual-wavelength all-fiber laser at 1.8 μm for the first time.