Three-stage MOPA 2 µm fiber laser for ZGP OPO pumping

A polarization-maintaining (PM) pulsed three-stage master oscillator power amplifier (MOPA) emitting at 2047 nm is reported, generating 19.8W of output power (396 μJ pulse energy) for a 50 ns pulse width at a repetition rate of 50 kHz. The output signal is linearly polarized and a diffraction limited beam quality is achieved. This MOPA laser is used to pump a doubly resonant ZnGeP2 (ZGP) optical parametric oscillator (OPO) in a linear cavity. A mid-IR output power of 8.1W, accordingly 162 μJ of pulse energy, and a conversion efficiency of 44 % are obtained in the 3-5 μm band.