Abstract: A polarization of a light signal is modulated to provide polarization tracking in a wireless optical communication system. The light signal having the modulated polarization, such as a sinusoidally varying polarization, is transmitted from an optical transmitter having polarization-maintaining fiber. The light signal having the modulated polarization is received at an optical receiver. A portion of the light signal is directed to an analyzer that detects the modulated polarization and generates an amplitude-modulated light signal corresponding to the modulated polarization. The amplitude-modulated light signal is directed to a tracking detector, such as a quad cell detector, that generates an amplitude-modulated electronic signal corresponding to the amplitude-modulated light signal. The amplitude-modulated electronic signal can be subsequently used to control or perform tracking of the optical receiver.

Abstract: A transmitted light signal, such as laser light, is modulated by a data signal and by a tracking signal. The tracking signal has a modulation depth that is substantially smaller than a peak-to-peak amplitude of the light signal. At reception, the tracking signal is recovered from the modulated light signal and is used to determine an orientation of a receiver with respect to the transmitted light signal.