Patent attributes
An optical detector system provides beam positioning data to an optical tracking system to facilitate optical communications. The optical detector system comprises a plurality of optical photodetectors. For example, a two-by-two array may be used. Incoming light passes through one or more optical elements, such as a lens and a dispersive optical element. A first portion of the beam entering the optical elements is directed into a first spot having a first area on the array. A second portion of the beam entering the optical elements is dispersed to form a second spot having a second area on the array that is larger than the first area. This combination of first portion and second portion of the beam incident on the array provides unambiguous information in the output of the photodetectors that is indicative of a position of the incoming beam with respect to the array.