Integrated multi-dithering controller for adaptive optics

Dimitrios N. Loizos, Ling Liu, Paul P. Sotiriadis, Gert Cauwenberghs, Mikhail A. Vorontsov, Stephen M. Hammel, Alexander M. J. van Eijk, Michael T. Valley, Mikhail A. Vorontsov
2007 Atmospheric Optics: Models, Measurements, and Target-in-the-Loop Propagation  
Effective compensation of phase noise in laser communication calls for fast, real-time, adaptive wavefront control. We present an analog, continuous-time, high-speed VLSI (Very Large Scale Integration) controller implementing multi-dithering perturbative gradient descent optimization of a direct measure of optical performance. The system applies parallel sinusoidal perturbations to the wavefront over a range of frequencies, and performs parallel synchronous detection of the metric signal to
more » ... ve the gradient components over each frequency band. The system operates over a wide range of frequencies, supporting applications of model-free adaptive optics extending from compensation of slow atmospheric turbulence to compensation of fast random phase fluctuations in the actuators and laser amplifiers. The system has been tested as a phase controller for a multiple laser beam wavefront propagating through a highly turbulent medium. The results indicate a compensation bandwidth exceeding 300 kHz matching the turbulence bandwidth.
doi:10.1117/12.736263 fatcat:oxu6l6bsjnddbfj2ytvqczeeli