Terabeam Corporation

Ronald D Steiger

Mark R Pratt

A tracking system and method in an optical communications system utilizing an optical communications beam. In one embodiment, the disclosed optical communications system includes a communications receiver circuit and a tracking circuit. The optical communications system generates a communications signal. The tracking system includes a tracking detector having a plurality of regions coupled to a corresponding plurality of tracking channel circuits. Each of the tracking channel circuits includes an optical detector coupled to receive the optical communications beam. The peak-to-peak amplitude modulation in the optical communications beam is measured by substantially reducing or removing a direct current (DC) offset present in the optical communications beam. In one embodiment, after the DC offset is substantially reduced or removed, the signal is then amplified, mixed with the communications signal and then filtered. The filtered signal is one of a plurality of tracking signal outputs, which are input to an alignment circuit. The alignment circuit is used to help maintain the alignment of the optical communications beam between the optical transmitter and receiver of the optical communications system. In one embodiment, each of the plurality of tracking signal outputs are also input into a gain control circuit. The gain control circuit is coupled to generate a gain control signal, which used to control the gain of variable gain amplifiers in the tracking channel circuits.

Method and apparatus for tracking an optical communications system

An integrated optical communications receiver/alignment system and method. In one embodiment, a method and an apparatus are disclosed in which a semiconductor substrate includes a plurality of outer optical detectors disposed in the substrate. An optically transparent center region such as for example an optical waveguide or an optical fiber is integrated in the semiconductor substrate in a central location relative to the plurality of outer optical detectors. The optically transparent center region is optically coupled to receive an optical communications beam and the plurality of outer optical detectors are employed for alignment and/or tracking purposes.

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Redmond, WA, United States of America

Ronald D Steiger