Numerical Modeling of Dual-wavelength Pumped Heavily-Ho3+-Doped Fluoroindate Fiber Lasers with Efficient Output at 3.92 μm

In this paper, laser emission at 3.92 μm in heavily-holmium-doped fluoride fibers using 888 nm and 1660 nm laser as pumping sources is investigated through numerical modeling. The dual-wavelength pumping system has lower threshold and higher slope efficiency than the single-wavelength pumping system at 888 nm. In addition, the system can decrease the heat load due to the 1660 nm input influencing the energy transfer up-conversion and cross-relaxation processes effectively, which indicates the possibility of raising the laser heat-damage threshold and providing high-power 3.92 μm laser generation. This research represents a novel method for improving the performance of 3.92 μm fiber lasers.