Document Type

Conference Paper

Publication Date


Publication Source

Proceedings of the 2006 AMOS Conference


We present the concept development of a novel atmospheric compensation system based on adaptive tiled fiber array architecture operating with target-in-the-loop scenarios for directed beam applications. The adaptive tiled fiber array system is integrated with adaptive beam director (ABD). Wavefront control and sensing functions are performed directly on the beam director telescope primary mirror. The beam control of the adaptive tiled fiber array aims to compensate atmospheric turbulence-induced dynamic phase aberrations and results in a corresponding brightness increase on the illuminated extended object. The system is specifically designed for tiled fiber system architectures operating in strong intensity scintillation and speckle-modulation conditions typical for laser-illuminated extended objects and includes both local (on-tile) wavefront distortion compensation and phase locking of sub-systems. The compensation algorithms are based on adaptive optimization of performance metrics. Local wavefront distortion compensation is performed using on-tile stochastic parallel gradient descent (SPGD) optimization of local speckle metrics directly measured on each fiber-tile. Phase locking is performed using SPGD optimization of a composed metric, that is, the metric combined from the local metrics. An experimental setup is developed to evaluate the feasibility of controlling beam quality by using speckle metrics based on the temporal analysis of the speckle pattern of light which is backscattered from a laser-illuminated extended object and recorded by a single photo-detector. The experimental setup is used to investigate beam quality improvement, adaptive process convergence, and the influence of the illuminated object shape.

Document Version

Published Version


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Maui Economic Development Board

Place of Publication

Maui, HI


Electro-optics Program