Line competition in an intracavity diode-pumped Yb: KYW laser operating at 981 nm

Oxxius Yb:KYW laser research today

Published in the Journal of the Optical Society of America B in 2011, this paper presents a detailed analysis of line competition in a Yb:KYW 981 nm intracavity laser — a phenomenon that directly limits achievable output power when multiple emission lines compete for the available gain. The Yb:KYW system, intracavity-pumped at 981 nm by a co-lasing transition, is particularly sensitive to this effect because its gain spectrum supports oscillation at 981 nm, 1000 nm, and 1025 nm simultaneously under standard operating conditions.

The model developed here identifies temperature as the key control parameter: by raising the temperature of the Yb:KYW crystal, the gain differential between the desired 981 nm line and competing lines can be increased sufficiently to enforce single-line operation. This insight is practically valuable for any laser system where quasi-three-level transitions must be favored over lower-threshold four-level alternatives — a challenge that appears across a broad range of Yb-doped gain media including Yb:KGW, Yb:YAG, and Yb:glass.

Relevance to compact laser design

Understanding and controlling line competition is essential for the development of compact, efficient Yb-doped lasers in the 980–1000 nm range — wavelengths of interest for pumping Er-doped fiber amplifiers, generating visible output via frequency doubling, and driving specialty fiber lasers. The analytical framework presented in this paper contributes to Oxxius’s broader expertise in diode-pumped solid-state laser design, which underpins the Single Frequency Laser and CW & Modulated Laser product lines.

Abstract

This paper proposes an analysis of a Yb:KYW laser emitting at intracavity pumped by a laser operating at . It gives some guidelines to optimize the laser performance. An output power of has been obtained at for a pump power of at . It presents a simple and original model to deal with the line competition between and the other lines at 1000 and and explains how a temperature increase can promote the laser emission. This approach could be useful for other lasers that are subject to line competition.