Gain-Switched Dual-Waveband Ho3+-Doped Fluoride Fiber Laser Based on Hybrid Pumping

Abstract

Using hybrid pumping by continuous-wave (CW) laser diodes at 1150 nm and a Tm3+-doped pulsed fiber laser at 1950 nm, we demonstrated a dual-waveband (DW) ~2.1- and ~3- $\mu \text{m}$ gain-switched Ho3+-doped fluoride pulsed fiber laser. The 1150-nm CW pumping provided population in the upper level of the ~3- $\mu \text{m}$ transition, while the 1950-nm pulse pumping modulated the population in the common level of the ~2.1- and ~3- $\mu \text{m}$ transitions, which can trigger simultaneous DW gain switching. By controlling the power ratio of 1150- and 1950-nm pumping, three switchable gain-switched pulse regimes ( $\sim 2.1~\mu \text{m}/ \sim 3~\mu \text{m}$ /DW ~2.1 and $\sim 3~\mu \text{m}$ ) were observed. In the DW regime, the maximum output powers of 136.6 and 26 mW at 2971.9 and 2062.3 nm were obtained with repetition rates of 50 and 25 kHz, respectively.