Northrop Grumman Systems Corporation

John Featherston

James M Cicchiello

Christopher A Archer

Frederick D Bean

Curtis J Harkrider

Jean Christopher Shelton

An optical communications system includes a modulator/demodulator (modem) to transmit outgoing communications data and to receive incoming communications data in a transceiver. A main detector is coupled to the modem to convert an optical signal representing the incoming communications data to an electrical signal for the modem. An adaptive data rate processor monitors the electrical signal from the main detector to determine a current power level for the optical signal. The adaptive data rate processor dynamically adjusts a data rate of the modem based on the determined current power level of the optical signal.

Optical transceiver with variable data rate and sensitivity control

A system includes a detector array having a plurality of level detectors to monitor an optical input signal. Each level detector of the detector array operates in a different operating range, and each operating range for each level detector has a different saturation level and a different cutoff level based on a power level of the optical input signal. A controller monitors the plurality of level detectors of the detector array to detect a present power level for the optical input signal by selecting the operating range that is associated with the level detector operating between its saturation level and its cutoff level.

Optical receiver sensitivity system

A free-space optical (FSO) transceiver can include a link predictor configured to estimate conditions for an FSO link over a window of time in the future. The FSO transceiver can also include a scheduler configured to assign outgoing packets to blocks of time in the window of time based on quality of service (QoS) parameters of each of the outgoing packets and on conditions in each block of time in the window of time.

Free space optical transceiver

A free-space optical (FSO) transceiver can include a transmission protocol configured to encapsulate outgoing network packets in by employing a reliable ordered protocol that relies on retransmission of lost data to form outgoing encapsulated packets. The transmission protocol controller can be configured to employ a congestion algorithm that optimizes throughput over a lossy link. The FSO transceiver can also include a transmitter configured to provide an output optical signal corresponding to the outgoing encapsulated packets over an FSO link.

Transmission protocol controller

An optical head is provided for a free space optical communications system. The optical head is utilized for transmitting and receiving modulated infrared laser beams. The optical head includes an optical amplifier, a circulator, an ultrafine-steering element, a fine-steering element, a course-steering element, and a fine track sensor. Additionally, a method is provided for facilitating airborne free space optical communications between an airborne host platform and a link platform. Each platform has an optical head which transmits and receives data via modulated infrared laser beams, wherein the host includes at least an optical head having a fine, coarse, and ultrafine steering element configured in a cascaded three-tier steering element architecture.

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Fort Wayne, IN, United States of America

John Featherston