Turbulence‐Resilient Coherent Receiver Array on CMOS‐Compatible Silicon Photonics for Free Space Optical Communications

ABSTRACT The growing demand for high‐capacity, long‐distance terrestrial and ground‐to‐space communication applications highlights the limitations of conventional transceivers, which are primarily designed for controlled data‐center environments. To address the unique challenges of free‐space optical communication, particularly wavefront distortions induced by atmospheric turbulence, we present and experimentally demonstrate a 4 × 4 array of coherent receivers integrated on a CMOS‐compatible silicon photonics (SiPh) platform. This receiver array performs spatial sampling of the incoming distorted wavefront, enabling enhanced signal recovery in turbulent and low‐power conditions. Central to our signal processing approach is the maximum‐ratio combining (MRC) algorithm, specifically designed to optimally combine spatially sampled signals and effectively mitigate turbulence‐induced phase and amplitude distortions. The system is experimentally validated under moderate atmospheric turbulence conditions using binary phase‐shift keying (BPSK) modulation, achieving nearly theoretical combining efficiency, restoring a clean eye diagram at −37.95 dBm average received power and a BER improvement from 1E‐2 (single receiver) to 1E‐15 (16 receivers with MRC).