We report on an ultra-efficient 1.5 μm Raman amplifier in methane-filled negative curvature hollow-core fiber. A 1.5 μm tunable CW DFB seed laser is coupled into the fiber together with a 1064 nm pump laser using a shortpass dichromic mirror, and then stimulated amplified by Raman scattering of methane. The maximum Raman conversion efficiency of 66.4 % was obtained in the 2 bar methane gas filled, 2 m long hollow core fiber with 50 mW coupled pump power and 22.6 mW coupled seed laser power, and the corresponding quantum efficiency is as high as to 96.3 %, which almost approaches the quantum limit. The introduction of the single frequency seed laser not only reduced the Raman threshold from 17.5 mW to 9.5 mW, but also narrowed the Stokes linewidth from 3.4 GHz to 2.1 GHz with a factor of 60%. This kind of gas filled hollow core Raman amplifier can be a potential method to obtain low threshold, narrow linewidth and high efficiency mid infrared laser source in various application.

Date Published: 24 October 2017
PDF: 6 pages
Proc. SPIE 10457, AOPC 2017: Laser Components, Systems, and Applications, 104570A (24 October 2017);

Published in SPIE Proceedings Vol. 10457:
AOPC 2017: Laser Components, Systems, and Applications
Shibin Jiang; Lijun Wang; Lan Jiang; Long Zhang, Editor(s)