Patent ID: 8396373

Claim:
A modulating retroreflector, comprising: a retroreflector positioned to receive an optical signal from a source through an entrance aperture and reflect the optical signal toward the source; an optical polarization modulator coupled with the retroreflector and positioned to modulate the polarization of the optical signal such that any interference from atmospheric scintillation is minimized; and a data processor coupled with the optical modulator and configured to produce a data stream, wherein the optical polarization modulator modulates the optical signal according to the data stream; a first optical receiver configured to receive light in a first polarization state; and a second optical receiver configured to receive light in a second polarization state, wherein: the first polarization state and the second polarization state represent approximately orthogonal polarization states; and the data processor compares a power received at the first optical receiver to a power received at the second optical receiver to differentiate between the first polarization state and the second polarization state and decode the optical signal from the source.