DIGITAL TURBULENCE COMPENSATION OF FREE SPACE OPTICAL LINK WITH AMPLIFIER MULTIMODE OPTICAL

We demonstrate digital turbulence compensation using a 12-spatial mode digital coherent receiver with a multimode pre-amplifier that provides a 6-dB sensitivity improvement. This combination acts similarly to ideal lossless adaptive optics. Coherent superposition of 12 spatial-modes reduced median BER from 0.1 to 1 x 10 -5 compared to traditional single-mode detection.