Abstract

Coherent combination of fiber lasers is a promising technique to overcome the power limitations of a single laser. The phase matching of a large number of fibers thus makes it possible to obtain high-energy lasers. Coherent beam combining has been the topic of tremendous works and can be achieved in either filled-aperture [1] or tiled-aperture [2] configuration. With the tiled-aperture configuration the maximum combination efficiency is limited to 66% due to the presence of grating lobes in far-field. With the filled-aperture configuration, it is possible to achieve one single output beam but the use of transmissive optics – such as diffractive optical elements – limits the scalability of the system, reducing the maximum achievable power. The Multi-Plane Light Conversion (MPLC) technology theoretically solves most of the problems inherent to previous techniques [3,4]. The theoretical combination efficiency is 100%. The technology uses only phase plates in reflection and mirrors, compatible with high power. Finally, it allows the integration of a fine beam steering function.

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