Laser communication system with source tracking

Abstract

A free space laser communication system that maintains dynamic alignment is presented. The system comprises two laser transceivers positioned a distance apart. Each transceiver includes the following components. A beacon laser is provided for transmitting a beacon beam at a first wavelength in a beam having a first divergence. A signal laser is provided for transmitting a signal beam carrying information to be transmitted to the other transceiver. A special telescope system is provided for collecting both the incoming beacon beam and the incoming signal beam from the other transceiver and for transmitting at least an outgoing signal beam. In a preferred embodiment the special telescope images the pupil of the telescope onto a tracking mirror. The tracking mirror pivots at least tilt and tip. The beacon beam is reflected from the tracking mirror and focused on a CCD array which monitors the direction of the beacon beam and provides a feedback signal to the tracking mirror to maintain the tracking mirror in positions which direct the beacon beam to a predetermined position on the CCD array and also directs the signal beam through a small aperture to a signal detector.