Tunable fiber gas Raman laser of 6 W at 2.9 μm by deuterium-filled hollow-core fiber

Here we demonstrate a high-power mid-infrared fiber gas Raman laser with a tunable wavelength range of 2851 nm to 2921 nm in a deuterium-filled hollow-core fiber pumped by tunable high-power pulsed erbium-doped fiber amplifiers. A maximum average power of 6 W (pulse energy of 3.5 μJ) is obtained in a 26.7 m HCF filled with 0.9 MPa deuterium at a pump wavelength of 1545 nm. It is, to the best of our knowledge, the highest power of mid-IR fiber gas Raman laser reported. The conversion efficiency is ∼14% relative to the output power of the pump source. The output power, spectra, pulse evolutions and the influence of polarization state on Raman power are systematically analyzed and discussed. A numerical model based on Maxwell-Bloch equations is established to describe the SRS of deuterium in the HCF. This work offers an effective method to obtain high-power tunable mid-IR fiber laser, which has important applications in related fields, and provides helpful guidance for fiber gas Raman laser.