Atmospheric turbulence mitigation through an integrated photonic circuit receiver

Experiments in free space optical communications have demonstrated high data rates over long distances as an alternative to radio relay communications systems. Over long distances, the free space optical channel experiences time varying attenuation and distortion due to random refractive index changes in the propagation path. The random changes in the propagation channel manifest themselves as random variations in the amplitude and phase profile of the transmitted light, producing turbulence induced fading. Additionally, the turbulent channel reduces the visibility of higher data rate communication channels. Various techniques for atmospheric turbulence mitigation have been demonstrated which seek to decompose the incoming beam into varying weights of a basis set and leverage coherent beam combining. We investigate a photonic integrated circuit receiver capable of decomposing an incoming distorted beam into various waveguide modes. Chip scale coherent beam combining is then used to recombine the decomposed modes.