Signal Intensity Deconvolution in Optical Receivers

In a photon-counting free-space optical communication receiver, the signal energy should be centered on the photo detector in order to maximize the received signal power. Random spatial fluctuations of the beam can be induced by atmospheric as well as mechanical phenomena. In order to control a compensator for driving the beam to the center of the detector, we must be able to infer the location of the centroid with only rudimentary spatial information (the number of photons that have hit each quadrant of the detector). We close this control loop by making a reduction to the task of signal intensity reconstruction via an inverse problem, proving non-asymptotic estimation error bounds for the previously published method and novel simplification, and presenting two novel estimation schemes that empirically perform better in near- and medium-range deep space settings. Our centroid estimation method is the first procedure in the literature proved to be consistent.