All Fiber Passively Q-Switched Mode-Locked Laser at 1195 nm Based on Ho³⁺-Doped ZBYA Fibers

This study presents the realization of an all-fiber passively Q-switched mode-locked laser operating at 1195 nm, employing a custom Ho 3+ -doped ZBYA (ZrF 4 -BaF 2 -YF 3 -AlF 3 ) fiber. The ZBYA fibers are fabricated through the rod-in-tube method. Utilizing a 0.7 m ZBYA fiber as the gain medium, an 1150 nm Raman fiber laser as the pump source, and a saturable absorber composed of a carbon nanotube film, we observed the generation of stable Q-switched mode-locked pulses within an all-fiber ring cavity. The achieved minimum pulse duration and maximum single pulse energy were 3.9 μs and1.13 μJ, respectively. Moreover, a maximum repetition rate of 19 kHz was achieved with a signal-to-noise ratio of 60 dB. Furthermore, mode-locked repetition rate is 8.62 MHz corresponding to a signal-to-noise ratio of 30 dB. Our findings underscore the potential of ZBYA fibers as promising gain media for the development of compact laser sources with significant pulse energy, operating in the 1.2 μm wavelength region.