Achieving a 15 μm fiber gas Raman laser source with about 400 kW of peak power and a 63 GHz linewidth

We have demonstrated for the first time, to the best of our knowledge, a novel and effective method to produce a 1.5 μm fiber source by means of Raman wavelength conversion in a gas-filled hollow core fiber. An ethane-filled, anti-resonance, hollow core fiber is pumped with a high peak power pulsed 1064 nm laser, generating a 1552.7 nm Stokes wave by pure vibrational stimulated Raman scattering of ethane. A maximum peak power of about 400 kW is achieved with a 6 m fiber length at 2 bars of pressure. The maximum Raman conversion efficiency is about 38%, and the corresponding laser slope efficiency is about 61.5%. The linewidth of the Stokes wave is 6.3 GHz. If a tunable pump laser is used, this kind of fiber source can easily achieve a broad tuning range near 1.5 μm.