Pure silica fiber Raman gain enabled high-power low-quantum defect fiber laser

Abstract

Reducing the quantum defect (QD) is a promising solution to mitigate the thermal load and lower system noise. Besides, owing to many advantages such as wavelength agility and non-photon darkening, Raman fiber laser (RFL) has attracted much attention in recent years. However, to date, there is no report in RFL on QD reduction by silica fiber, which is the most common gain medium with mature fabrication technology of high-power RFL. In this paper, we propose and experimentally demonstrate a ten-watt-level low-QD RFL gained by a piece of commercial silica fiber. The QD can be reduced to 0.56 %, corresponding to a laser power of 6.2 W. After system optimization, the output power can be scaled up to 17.7 W, with a QD of 1.48 % and a slope efficiency of 72.0 %. To the best of our knowledge, this is the lowest QD ever reported in fiber laser based on pure silica gain. This work can offer an effective and low-cost solution for fiber laser system with reduced heat production.