Abstract: An optical receiver for use in free space communication from a transmitter to the optical receiver is configured for receiving optical signals from the transmitter. The optical receiver includes optics for collecting the optical signals, a demodulator for converting the optical signals so collected into a data stream, a signal processing unit for processing the data stream into an analog signal, and an analog-to-digital converter for converting the analog signal into a digital output. The demodulator includes a plurality of apertures and at least one Fabry-Perot etalon, through which at least a portion of the optical signals is transmitted. The demodulator also includes at least one phase detection region for detecting at least the portion of the optical signals transmitted through the at least one Fabry-Perot etalon to form a phase signal.

Abstract: An imaging method and associated system for producing high-resolution images. The method includes illuminating an object or scene with coherent radiation such as beams from a laser and then, collecting scattered light with a plurality of subapertures rather than a single large aperture. The method continues with coherently detecting, such as with heterodyne detection, the scattered light to measure the complex amplitude incident on each subaperture and digitally reconstructing images from the coherently detected light for the subapertures. Then digital co-phasing is performed on the subapertures using an image sharpness or quality metric to form an image having the resolution of the total subaperture area. The method may also include determining an aimpoint in the formed image, calculating a phase screen, directing laser beams through the subapertures towards the aimpoint, and co-phasing the laser beams by applying the phase screen to form a single beam.