Abstract: A system and method for producing an eye safe laser communication system. The system and method detects an interfering object in the optical path and cuts off or reduces the power in the communication beam to safe levels. In one embodiment, a second laser diode transmitter and receiver is installed in each network node. The laser transmitter is pointed at a corresponding network node and the pulses travel in parallel with the communication beam. The pulses are reflected back to the transmitting node where they are detected. Their flight time is measured. When an interfering object is present, in one scenario, the pulses bounce of the interfering object and return to the receiver in the transmitting node, resulting in a reduced flight time. This reduced flight time is interpreted as an interfering object and the beam is shut down or reduced to a safe level. In a second scenario, the interfering object absorbs the detection beam.

Abstract: A system and method for controlling the power of a transmitter helps to ensure that the transmitted signal is within the dynamic range of the intended receiver. The transmitted signal is received by the receiver. The received signal strength is measured to determine its power level in relation to the dynamic range of the receiver. Where the signal strength is too high, the transmitter is slewed to effectively decrease its pointing accuracy, thereby causing a lower-power portion of the transmitted signal to impinge upon the receiver. Similarly, where the signal strength falls below a desired level, the transmitter is slewed back toward the center-pointing position, effectively increasing its pointing accuracy, and thereby increasing the signal strength received at the receiver.

Abstract: A free-space laser communication system. The system is comprised of a large number of picocells. Each picocell comprises a base station providing conventional communication with at least one user but typically several or many users. Each base stations comprise at least two laser transceivers each transceiver having a pointing mechanism for automatic alignment. These transceivers provide communication with other base stations, relay information between other base stations or transmit information to conventional communication systems. The picocells cover relatively small geographical ranges such as about 100 meters. Applicant has demonstrated that at these distances atmospheric effects attenuating laser beams are not a serious problem. In a preferred embodiment the base stations generally comprise four laser transceivers with micro processor controlled pointing equipment which are aligned automatically to point at other base stations and an RF transceiver to provide communication with users.

Abstract: A system and method for large building high bandwidth communication. An interface station is located on or near the building for providing high bandwidth communication between an external communication network and at least one, but typically several or many, free space optical distribution transceivers. Each free space optical distribution transceiver provides two-way optical communication utilizing beam splitters with at least two but typically several or many free space optical user transceivers within the large building. In a preferred embodiment each of several free space laser distribution transceivers are located on the top of a ten-story building and transmits information to free space laser user transceivers located on each of the ten stories of the building. Beam splitters are mounted on the windows of each floor to direct a portion of the laser beam from the roof-mounted transceiver to the user laser transceiver located on each floor.