Multi-mode rate equations have been developed to investigate mode competition in high-power acousto-optically Q-switched planar waveguide lasers. The mode competition arises from coupling effects and temporal losses in the transform between guided modes and free-space propagation. Pulse-to-pulse instability and temporal beam distortions are enlarged by mode competition when the laser works in the multi-mode regime. The influence of parasitic oscillation is also discussed. A Nd:YAG planar waveguide laser has been established with a folded hybrid/unstable resonator. A maximum average power of 83 W with a beam propagation factor Mx2 × My2 = 1.2 × 1.4 is obtained. The theoretical simulation agrees well with the experimental observation. © 2006 Elsevier Ltd. All rights reserved.
- Mode competition
- Planar waveguide laser