<title>Performance of various branch-point tolerant phase reconstructors with finite time delays and measurement noise</title>

Abstract

This study extends branch point tolerant phase reconstructor research to examine the effect of finite time delays and measurement error on system performance. Branch point tolerant phase reconstruction is particularly applicable to atmospheric laser weapon and communication systems, which operate in extended turbulence. We examine the relative performance of a least squares reconstructor, least squares plus hidden phase reconstructor, and a Goldstein branch point reconstructor for various correction time-delays and measurement noise scenarios. Performance is evaluated using a wave-optics simulation that models a 100km atmospheric propagation of a point source beacon to a transmit/receive aperture. Phase-only corrections are then calculated using the various reconstructor algorithms and applied to an outgoing uniform field. Point Strehl is used as the performance metric. Results indicate that while time delays and measurement noise reduce the performance of branch point tolerant reconstructors, these reconstructors can still outperform least squares implementations in many cases. We also show that branch point detection becomes the limiting factor in measurement noise corrupted scenarios.