Nanosecond pulsed narrow-linewidth all-fiber source for ZGP-OPO pumping

Abstract

We demonstrate a pulsed three-stage master oscillator power amplifier (MOPA) at a wavelength of 2047 nm and its application for mid-IR generation via pumping a ZnGeP2 (ZGP) optical parametric oscillator (OPO). A maximum MOPA output power of 19.8 W is reached while achieving a diffraction limited beam quality M2 <1.1. By applying the MOPA setup to pump a ZGP crystal in a linear OPO cavity, a combined signal and idler mid-IR output power of 8.1 W is reached. For the highest mid-IR output power, a mid-IR conversion efficiency of 44 % and beam quality factors M2 of 2.2 and 2.0 are determined for signal and idler, respectively.

12.2 W ZGP OPO pumped by a Q-Switched Tm3+:Ho3+-codoped fiber laser

“…This marks a significant improvement of 50 % compared to previous fiber laser pumped ZGP-based OPOs. 9,12 For lower incident pump power levels, even higher conversion efficiencies, up to 47.8 %, are demonstrated. This is an absolute efficiency improvement of about 15 % compared to similar previously published setups.…”

“…[9][10][11] Recently, diode seeded MOPA systems have proven to be effective pump sources. The conversion efficiencies were highly increased with efficiencies up to 59 % and average MWIR output powers of 8.1 W. 12,13 This efficiency boost is primarily attributed to the unique pulse shaping capability of such systems. However, these systems face challenges in power scaling due to the use of various custom-made components that struggle to handle high power and pulse energies.…”

High-pulse-energy actively Q-switched Tm-doped photonic crystal fiber laser operating at 2050 nm with narrow linewidth

“…Fiber-laser-pumped optical parametric oscillators based on nonlinear crystals like Zinc Germanium Phosphide (ZGP) have been shown to generate high power and pulse energies in the mid-IR efficiently. [1][2][3] The requirements on their pump lasers include high pulse energies and average output powers with ideal beam quality and narrow linewidth at wavelengths longer than 2 µm, where ZGP exhibits a lower background absorption. 4 TDFLs are well-known for providing high output powers with diffraction-limited beam quality but their extractable pulse energy in the nanosecond-regime is generally limited by the onset of parasitic lasing and fiber nonlinearities.…”