Recent advances in coupled laser cavity design
Leger, James R.
Date of Issue2013
Laser Resonators, Microresonators, and Beam Control (15th : 2013 : San Francisco, USA)
School of Electrical and Electronic Engineering
External cavity coherent beam combining represents a path forward to higher fiber laser radiance, with several groups demonstrating scalable approaches. In this paper, we review recent advances in coupled laser cavity design. In particular, we compare various designs and describe the pros and cons of each with regard to sensitivity to path length errors. Experimental measurements using a specially designed dual-core fiber demonstrate the modal loss from a superposition architecture. A second area of investigation is concerned with Q-switch suppression in coupled laser cavities. The increased cavity loss that accompanies path length errors in the laser arms can suppress lasing, causing an energy build-up in the laser inversion. When the path length errors are removed and the cavity resumes its low loss state, the stored energy can be released in a manner analogous to Q-switching, creating a giant laser pulse. Since the peak power of this pulse can be many orders of magnitude larger than the cw power, the high instantaneous intensity can cause irreparable damage to optical components. We investigate passive systems that are designed to suppress this unwanted Q-switching by allowing alternative lasing paths to clamp the gain.
© 2013 Society of Photo-Optical Instrumentation Engineers (SPIE). This paper was published in Proceeding of SPIE, Laser Resonators, Microresonators, and Beam Control XV and is made available as an electronic reprint (preprint) with permission of SPIE. The paper can be found at the following official DOI: [http://dx.doi.org/10.1117/12.2005628]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.