Exelis Inc.

Itt Manufacturing Enterprises, Inc.

Next Generation Systems, Inc.

Mcknight, Brent H.

Mcknight, John D.

James A Cunningham

Dean S Grinch

Daniel L Baber

Donald Fisher

David R Wickholm

Nathan Andrew Kragick

Gary G Warden

Donald Scott Fisher

David Wickholm

A technique for generating a data signal and a beacon signal for free space optical communications involves generating a data signal having a first optical wavelength and a beacon signal having a second optical wavelength. The data signal is encoded with data via modulation at a first modulation rate. The beacon signal is an inverted version of the data signal and can be further modulated at a second modulation rate that is less than the first modulation rate. The data and beacon signals are optically combined to produce a combined signal in which power attributable to the beacon signal is interleaved with and substantially non-overlapping temporally with power attributable to the data signal. The combined signal is amplified via a fiber amplifier, and the combined signal is supplied to transmitter optics for transmitting the data signal and the beacon signal into free space.

Amplification of interleaved optical signals

A technique for simultaneously transmitting wide and narrow optical beacon signals includes generating a laser beam and splitting the laser beam into a first signal on a first path and a second signal on a second path via a wavelength-dependent beamsplitter. A wide beacon signal having a first beam divergence is generated from the first signal, and a narrow beacon signal having a second, lesser beam divergence is generated from the second signal. The wavelength of the laser beam determines an allocation of the laser energy between the wide and narrow beacon signals based on transmittance/reflectance characteristic of the beamsplitter at that wavelength. The wide and narrow beacon signals are simultaneously transmitted in a overlaid manner into free space to support acquisition and tracking in a free-space optical communication system. The beamsplitter can simultaneously transmit or reflect substantially all of a data signal at a different wavelength.

Technique for simultaneously transmitting wide and narrow optical beacon signals

A technique for acquiring and tracking terminals in a free-space laser communication system involves exchanging beacon laser beams between the terminals to acquire and then track the terminals such that data laser beams exchanged by the terminals for communication are steered based on feedback from detection of the beacon laser beams. The beacon laser beams used for acquisition have a greater beam divergence than those used for tracking. Gimbals provide coarse steering of the data laser beams, and steering mirrors provide fine steering. GPS position data exchanged via an RF link can be used for initial pointing of the beacon laser beams for acquisition. The beacon laser beams can be chopped such that all terminals can use the same beacon wavelength and are distinguished by using different chopping frequencies. By detecting a chopped signal, the position sensor detector can be AC coupled to reduce sensitivity to solar radiation and glint.

Acquisition, pointing, and tracking architecture for laser communication

Systems and methods for providing fractional bandwidth communication channels in classes of service that do not normally support these types of channels. In one embodiment, a method comprises receiving one or more frames, wherein each frame contains non-QoS header information, classifying the one or more frames based on the corresponding non-QoS header information and scheduling delivery of the one or more frames based upon corresponding frame classifications, wherein frames in classifications corresponding to QoS circuits are scheduled in a manner that meets QoS requirements associated with the QoS circuits. When the frames are classified, they are forwarded to dynamically allocated queues corresponding to the respective classifications. Frames are scheduled for delivery from the queues according to a modified bin-filling algorithm that is designed to meet the QoS requirements of the respective circuits. This method may be implemented, for example, in a Fibre Channel Classor Classfabric.

Systems and methods for providing quality of service (QoS) in an environment that does not normally support QoS features

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Dayton, OH, United States of America

James A Cunningham