Mode-locked thulium/holmium-doped fiber laser utilizing manganese violet saturable absorber

2 mu m pulsed lasers have slowly gathered attention over the years for their promising potential in the medical field and sensing. We report the fabrication of a saturable absorber (SA) made by coating manganese violet (MV) on an arc-shaped fiber and the successful utilization of this SA to generate mode-locked pulses in a thulium/holmium-doped fiber laser (THDFL). This is the first demonstration of mode-locking by using MV as a saturable absorber. The MV was first synthesized using hydrothermal method and then drop-casted onto a homemade arc-shaped fiber. The generated mode-locked pulses have a center wavelength of 1908.9 nm, a fundamental repetition rate of 12.27 MHz and a pulse width of 1.27 ps. The maximum output power of the laser was measured as 3.02 mW with a slope efficiency of 1.36 %. The calculated pulse energy and the peak power are 246 pJ and 193.7 W, respectively. This work demonstrates the potential of MV, which belongs to the family of ammonium metal phosphates, as a saturable absorber used for mode-locked laser operations in the 2 mu m region.