Hundred-watt-level phosphosilicate Raman fiber laser with less than 1% quantum defect

Abstract

Quantum defect (QD)-induced high thermal load in high-power fiber lasers can largely affect the conversion efficiency, pose a threat to the system security, and even prohibit the further power scaling. In this Letter, we investigate evolutions and influences of the reflectivity of the output coupler, the length of phosphosilicate fiber, and the pump bandwidth, and demonstrate a hundred-watt-level low-QD Raman fiber laser (RFL). The RFL enabled by the boson peak of phosphosilicate fiber achieves a maximum power of 100.9 W with a reduced QD down to 0.97%; the corresponding conversion efficiency reaches 69.8%. This Letter may offer not only an alternative scheme for a high-power, high-efficiency fiber laser, but also great potential on the suppression of thermal-induced effects such as thermal mode instability and the thermal lens effect.

Functional Fibers and Functional Fiber-Based Components for High-Power Lasers

“…An increased understanding of how manufacturing method influences the properties of these materials benefits new fibers generated from new compositions. Moreover, it has been reported that the quantum defect induced high thermal load in HPFLs can be effectively eliminated in phosphorus-doped fiber [480][481][482][483][484][485][486][487][488] and over the hundred-watt level fiber laser with less than 1% quantum defect [486] has been demonstrated. From a more intrinsic view of light-matter interactions, the increment of both P 2 O 5 and B 2 O 3 continues to reduce heat generation and decreases the value of dn/dT [36,37], which suppresses the induction to parasitic effects such as SBS and TMI as well.…”

“…In addition to developing fiber lasers with higher output power and multi-dimensional controllability, there is an urgent demand for real-time analysis of laser beam characteristics, i.e., the mode decomposition (MD) [483][484][485][486][487][488][489][490][491]. Beam characterization represented by MD technology and beam quality measurement is an important tool for further study of fiber lasers.…”