Methods, systems, and apparatus for global multiple-access optical communications

A method of multiple-access optical communications at a satellite in geostationary Earth orbit (GEO), the satellite in GEO comprising a first telescope in optical communication with a focal plane array (FPA), the method comprising:

• receiving, via the first telescope from a satellite in low-Earth orbit (LEO), at least one inbound free-space optical signal;
• detecting the at least one inbound free-space optical signal at the FPA;
• and
• transmitting an outbound free-space optical signal from the satellite in GEO in response to detection of the at least one inbound free-space optical signal.

An optical receiver for multiple-access optical communications at a satellite, the optical receiver comprising:

• a first telescope having a first field of view of at least about 20° to receive a plurality of inbound free-space optical signals, each inbound free-space optical signal in the plurality of inbound free-space optical signals being at a first wavelength;
• a bandpass filter, in optical communication with the first telescope, to transmit light at the first wavelength and reject light at other wavelengths;
• a focal plane array (FPA), in optical communication with the first telescope, to detect the plurality of inbound free-space optical signals;
• a read-out integrated circuit, operably coupled to the FPA, to read out the FPA asynchronously with respect to modulation of the plurality of inbound free-space optical signals;
• and
• a controller, operably coupled to the FPA, to monitor trajectories of the plurality of inbound free-space optical signals across the FPA.