Thulium/holmium fiber laser with Ti2AlN MAX phase-coated arc-shaped fiber for mode-locked pulse generation

Abstract. A mode-locked thulium–holmium fiber laser operating in the 2.0-μm wavelength region was demonstrated using a MAX phase titanium aluminum nitride (Ti2AlN)-based saturable absorber (SA). The Ti2AlN was prepared in the solution form and then drop-casted onto a homemade arc-shaped fiber, which served as the SA device. The mode-locked pulses were generated when the pump power was at 119 mW, and the pulses were sustained up to a pump power of 249 mW. The mode-locked fiber laser using the Ti2AlN-based SA operated with a center wavelength of 1900.6 nm, having a repetition rate and a pulse width of 12.14 MHz and 1.61 ps, respectively. At the maximum pump power, the mode-locked pulses had maximum pulse energy of 0.35 nJ and peak power of 216 W. We propose the generation of short pulses using a MAX phase-based SA that could be useful for various applications in the eye-safe region.