US Patent 10965379 Coherent receiver for free space optical communications and lidar

An optical receiver is provided that includes a detector array of multiple detector elements, and processing circuits coupled to the multiple detector elements. The detector array is configured to receive light from an external source, mix the light with light from a local oscillator to generate a spatial fringe across the detector array. The multiple detector elements are configured to convert respective portions of the spatial fringe incident on the multiple detector elements to corresponding electrical signals. The processing circuits are configured to process the electrical signals. This includes the processing circuits configured to sum those of the corresponding electrical signals from one or more of the multiple detectors, and subtract the sum from a second sum of those of the corresponding electrical signals from one or more other of the multiple detectors.