Passive Laser Beam Combining With Intracavity Interferometric Combiners

In this paper, we present an approach for passive laser beam combining using plane-parallel intracavity interferometric combiners. With this approach, efficient coherent combining of Gaussian laser beams, transverse single high-order-mode laser beams, and even transverse multimode laser beams is possible. We experimentally obtained a combining efficiency of about 90% when coherently combining 16 solid-state laser channels, as well as when coherently combining four fiber laser channels. We also present an arrangement for simultaneous coherent combining and spectral combining, which could possibly overcome current upscaling limits. We present the basic coherent combining approach, review our past and recent investigations and results with both solid-state and fiber laser configurations, and discuss the possible upscaling and future prospects of this approach.