NASA is presently developing the first all-optical high data rate satellite relay system, LCRD. To be flown on a geosynchronous satellite, it will communicate with DPSK and PPM modulation formats up to 1.244 Gbps. LCRD flight payload is being developed by NASA’s Goddard Space Flight Center. The two ground stations, one on Table Mountain in CA, developed by NASA’s Jet Propulsion Laboratory, and another on a Hawaiian island will enable bi-directional relay operation and ground sites diversity experiments.
A free space optical communication link with simulated atmospheric turbulence investigation using un-cooled Mid-Wave Infrared (MWIR) system. Uncooled pulsed Quantum Cascade Laser was used as transmitter and photoelectromagnetic detector as receiver. For high photon efficiency and to eliminate QCL thermal effects signal was modulated at 32-ary Pulse Position Modulation (PPM) scheme. Concept enables extremely small and atmospheric propagation efficient optical communication system.
The LCRD will demonstrate optical communications relay services between a geosynchronous satellite and Earth over
an extended period, and thereby gain the knowledge and experience base that will enable NASA to design, procure, and
operate cost-effective future optical communications systems and relay networks. LCRD is the next step in NASA
eventually providing an optical communications service on the Next Generation Tracking and Data Relay Satellites
(TDRS). LCRD will demonstrate some optical communications technologies, concepts of operations, and advanced
networking technologies applicable to Deep Space missions. In this paper we describe the integrated dual format
(PPM/DPSK) modem testbed development and performance.