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Proceedings Paper

Phase-locking of tiled fiber array using SPGD feedback controller
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Paper Abstract

We present the laboratory experiments of phase locking of a multi-channel tiled fiber array using a stochastic parallel gradient descent (SPGD) feedback controller demonstrating the compensation effect of the simulating phase-induced distortions based on the model-free optimization of the received signal strength. An all-polarization-maintaining (PM)-fiber optical configuration is used to simplify the free-space transceiver system. The atmospheric aberrations are simulated by a multi-channel integrated optical phase modulator which obtains input control voltages from an array of multi-channel independent sinusoidal signal generators. A similar multi-channel phase modulator which obtains input control voltages from a computer-based SPGD controller is used to compensate the simulating phase distortions. The experimental results show that the constructive interference state is reached through phase locking of the multi-channel tiled fiber array for phase distortions up to 180 hertz for each channel. The update rate of the computer-based SPGD controller is ~16,000 iterations per second. The average compensation bandwidth is about 310 Hz

Paper Details

Date Published: 23 August 2005
PDF: 9 pages
Proc. SPIE 5895, Target-in-the-Loop: Atmospheric Tracking, Imaging, and Compensation II, 58950P (23 August 2005); doi: 10.1117/12.617415
Show Author Affiliations
Ling Liu, Univ. of Maryland (United States)
Mikhail A. Vorontsov, Univ. of Maryland (United States)
U.S. Army Research Lab. (United States)

Published in SPIE Proceedings Vol. 5895:
Target-in-the-Loop: Atmospheric Tracking, Imaging, and Compensation II
Michael T. Valley; Mikhail A. Vorontsov, Editor(s)

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