From Event: SPIE Optical Engineering + Applications, 2016
The Laser Communication Relay Demonstration is NASA’s multi-year demonstration of laser communication to a geosynchronous satellite. We are currently assembling the optical system for the first of the two baseline ground stations. The optical system consists of an adaptive optics system, the transmit system and a camera for target acquisition. The adaptive optics system is responsible for compensating the downlink beam for atmospheric turbulence and coupling it into the modem’s single mode fiber. The adaptive optics system is a woofer/tweeter design, with one deformable mirror correcting for low spatial frequencies with large amplitude and a second deformable mirror correcting for high spatial frequencies with small amplitude. The system uses a Shack- Hartmann wavefront sensor. The transmit system relays four beacon beams and one communication laser to the telescope for propagation to the space terminal. Both the uplink and downlink beams are centered at 1.55 microns. We present an overview of the design of the system as well as performance predictions including time series of coupling efficiency and expected uplink beam quality.
Lewis C. Roberts, Rick Burruss, Santos Fregoso, Harrison Herzog, Sabino Piazzola, Jennifer E. Roberts, Gary D. Spiers, and Tuan N. Truong, "The adaptive optics and transmit system for NASA's Laser Communications Relay Demonstration project," Proc. SPIE 9979, Laser Communication and Propagation through the Atmosphere and Oceans V, 99790I (Presented at SPIE Optical Engineering + Applications: August 31, 2016; Published: 19 September 2016); https://doi.org/10.1117/12.2238589.
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