Fast aberration-correcting algorithm for an SLM-based optical switch

We propose a novel method to efficiently correct the aberration in a free-space optical switch, where a spatial light modulator (SLM) is used to control wavefronts. A particle swarm optimization (PSO) method is applied to finding the optimum set of Zernike modes to compensate the aberration. We find out that the obtained coefficients of the lower-order modes and those of the higher-order ones exhibit a linear relationship when the optimization flow is interrupted by the local optima. We can drastically reduce the time for the calibration by using this relationship among the Zernike coefficients.