Compact high-power MIR laser through pulse fiber laser pumped PPMgLN-based OPO

We present a compact high-power mid-infrared laser (MIR) through pulse fiber laser pumped PPMgLN-based optical parametric oscillator (OPO). The pulse fiber laser consists of a gain-switched pulse fiber laser seed and one stage fiber amplifier, which features an all polarization-maintained fiber structure with a linearly polarized maximum average power output of 40 W. A semi-external-cavity structure is utilized to simplify the OPO system and to mitigate the thermal lens impact under high-power operation. Mid-infrared output of 4.75 W at 3.81 µm is achieved under pump power of 31.31 W at pulse repetition rate of 50 kHz, corresponding to pump to MIR conversion efficiency of 15.17%. High beam quality MIR output is obtained, in which the beam quality factor (<i>M</i> ²) is measured to be 1.72 for horizontal and 1.87 for vertical, respectively.