Phosphosilicate Fiber-Based Low Quantum Defect Raman Fiber Laser with Ultrahigh Spectral Purity

Abstract

The phosphosilicate fiber-based Raman fiber laser (RFL) has great potential in achieving low-quantum defect (QD) high-power laser output. However, the laser’s performance could be seriously degraded by the Raman-assisted four-wave mixing (FWM) effect and spontaneous Raman generation at 14.7 THz. To find possible ways to suppress the Raman-assisted FWM effect and spontaneous Raman generation, here, we propose a revised power-balanced model to simulate the nonlinear process in the low-QD RFL. The power evolution characteristics in this low-QD RFL with different pump directions are calculated. The simulation results show that, compared to the forward-pumped low-QD RFL, the threshold powers of spontaneous Raman generation in the backward-pumped RFL are increased by 40% and the Raman-assisted FWM effect is well suppressed. Based on the simulation work, we change the pump direction of a forward-pumped low-QD RFL into backward pumping. As a result, the maximum signal power is increased by 20% and the corresponding spectral purity is increased to 99.8%. This work offers a way for nonlinear effects controlling in low-QD RFL, which is essential in its further performance scaling.

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.…”

“…The mode information carried by laser beam is the key to understand intrinsic properties and transmission characteristics of HPFLs, which are challenging to be completely analyzed even with complicated measurement methods [489,492,493]. However, it should be noted that the emerging machine learning technology is expected to provide an effective and accurate technical scheme for online analysis [488][489][490][491][492][493][494][495][496].…”

Contribution of different factors in heat production in Yb3+-doped fiber laser: a review

“…20 The QD limits the conversion efficiency, but more importantly, it is the main source of thermal load in FLs. 31 Karimi: Contribution of different factors in heat production in Yb 3+ -doped fiber laser: a review Optical Engineering 110902-2 November 2022 • Vol. 61 (11) The Yb 3þ -doped FL has fewer QDs and an energy depletion mechanism.…”

“…30 Also, phosphosilicate fiberbased RFL has great potential in achieving ultralow QD high-power laser output. 31 Tandem pumping brings the pump and signal wavelengths closer together and reduces the QD. 30 Another option is using the RFLs.…”