Efficient 1054 nm Raman Random Fiber Laser

Abstract

Low–coherence laser is regarded as the key to mitigating laser–plasma instability (LPI) in laser–driven inertial confinement fusion (ICF), where LPI can decrease the laser energy coupled to the target. With the merits of low coherence, high spectral stability, and flexible output characteristics, the Raman random fiber laser (RRFL) is considered to be a candidate light source in ICF. In this paper, the 1054 nm RRFL with high slope efficiency is achieved for the first time. In the RRFL pump source design section, we have optimized the ytterbium–doped fiber (YDF) length by simulation and amplified the power by Master Oscillator Power Amplifier (MOPA) to realize a 1011 nm YDF laser with 47.3 dB optical signal–to–noise ratio (OSNR). In terms of RRFL cavity design, a fiber loop mirror and Rayleigh scattering in the HI 1060 Flex fiber provide wideband point feedback and random distributed feedback, respectively. Based on this system, we achieve an RRFL output with 0.4 nm half–maximum full width, 182% slope efficiency, and 41.3 dB OSNR. This work will provide guidance for the application of RRFL in high–energy–density physics research.