118 nm-wavelength-tunable Er3+-doped ZBLAN passively mode-locked fiber laser

A wide wavelength tunable Er3+: ZBLAN passively mode-locked fiber laser operating in the 3 μm mid-infrared region with Ti3C2Tx as a saturable absorber has been presented. The wavelength was selected by rotating the blazed grating. The fiber laser can achieve stable continuous-wave mode-locked state in the wide wavelength tuning range of 118.6 nm (2709 nm~2827.6 nm) with a repetition frequency of 28.3 MHz. When the launched pump power is 1.77 W, a stable mode-locked pulse with a maximum output power of 137.4 mW can be obtained at 2786 nm, and the corresponding single pulse energy is ~4.9 nJ. However, the pulse duration was not measured by the autocorrelator due to the limited output power. To the best of our knowledge, this is a passively mode-locked fiber laser at ~3 μm with the largest tuning range based on a saturable absorber. The presented widely wavelength tunable laser is a stable seed source for applications in laser medical treatment, spectroscopy and supercontinuum generation.