Optimal coherent beam combining based on Multi-Plane Light Conversion for high throughput optical feeder links

Authors: Antonin Billaud,¹ Fausto Gomez,¹ David Allioux,¹ Nicolas Laurenchet,¹ Pu Jian,¹ Olivier Pinel,¹ Guillaume Labroille¹

¹Cailabs (France)

Abstract

Free-space optical links are being considered for high throughput feeder links in satellite communication. Optical power up to 500 W is required at the optical ground terminal, which represents a challenge for current technologies. One way to scale power whilst preserving beam quality is coherent beam combining. Here, we present a novel technique based on Multi-Plane Light Conversion, consisting in a spatial multiplexer whose output modes form a Gaussian beam when superimposed constructively. The beam combiner is fully reflective, enabling kW optical power. We demonstrate a mode purity and a total efficiency higher than the conventional tiled apertures technique.