Terabeam Corporation

Micah J Barclay

Jeffrey C Adams

Mark R Pratt

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. Such tracking can include adjustment of an orientation of the optical receiver with respect to the light signal received from the transmitter.

Method and apparatus for polarization tracking in wireless optical communication systems

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.

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Redmond, WA, United States of America

Micah J Barclay