Hybrid dual-wavelength pumped gain-switched single-frequency pulsed Tm-doped fiber laser at 2.1 μm

An efficient gain-switched single-frequency pulsed Tm3+-doped fiber laser at 2.1 μm based on a distributed Bragg reflector short cavity (centimeter-level-long) under hybrid dual-wavelength pumping is experimentally demonstrated. By combining a 1570 nm pulsed fiber laser and a 793 nm continuous-wave (CW) laser diode (LD) pumps to precisely control pump parameters for initiating gain-switching process, stable single-longitudinal-mode pulsed laser at 2097.48 nm is generated with an average output power of approximately 5 mW. The fiber laser produces pulses with a tunable pulse width from 26 to 97 ns and an adjustable repetition rate from 30 to 100 kHz. The implemented 793/1570 nm hybrid dual-wavelength pumping scheme enables a lower lasing threshold while maintaining the pulse performance, as verified by comparative experiments with 793 nm and 1610 nm pumps. This is the first demonstration of a gain-switched single-frequency pulsed Tm3+-doped fiber laser operating at the extended wavelength of 2.1 μm.