Abstract:The adaptive optics (AO) technology without a wave-front sensor is simple and has more application fields than conventional AO technologies. The theory basis of the AO system based on stochastic parallel gradient descent (SPGD) from the convergence, the stability, and the averaged convergence rate is analyzed, where SPGD is used to control the AO system. The results show that the AO system based on SPGD can obtain good convergence and stability, and the fast convergence rate, which is in inverse proportion to $
\sqrt n
$
\sqrt n
(n is the number of control parameters).