In this paper we consider numerical model of an adaptive coherent fiber array system that is utilized for remote transmission of laser power to an active photovoltaic cell (PVC)-based receiver array. The PVC array performs optical-to-electrical power conversion, and provides a feedback signal that is sent to the laser transmitter via optical and/or RF link. The feedback signal is utilized for real-time adaptive shaping of laser power density distribution at the PVC array for achieving the following objectives:
(a) Minimization of laser power losses caused by mismatch between size and shape of the transmitter beam footprint and the PVC array. For optimal performance, the projected laser beam footprint should be adaptively changed to fit the PVC area under continuously changing turbulence strength, distance to the target, system field of view, platform jitter, etc. and
(b) Reduction of laser beam power fluctuations inside the PVC caused by errors in target/load tracking, and laser beam aimpointing and aimpoint stabilization.
In the numerical simulations the optical power with adaptive beam shaping was performed over 3 km and 7 km distances in turbulent atmosphere. The results demonstrate ability of the adaptive fiber array systems with 21 sub-apertures considered, for efficient adaptive beam shaping resulting in significant power beaming efficiency improvement.
A novel scintillation resistant wavefront sensor based on a densely packed array of classical Zernike filters, referred to as the multi-aperture Zernike wavefront sensor (MAZ-WFS), is introduced and analyzed through numerical simulations. Wavefront phase reconstruction in the MAZ-WFS is performed using iterative algorithms that are optimized for phase aberration sensing in severe atmospheric turbulence conditions. The results demonstrate the potential of the MAZ-WFS for high-resolution retrieval of turbulence-induced phase aberrations in strong scintillation conditions for atmospheric sensing and adaptive optics applications.