Multi-rate Differential Phase Shift Keying Optical Communications

Organization: MIT Lincoln Laboratory
Year: 2018

Five years ago, the Lunar Laser Communications Demonstration (LLCD) changed the communications paradigm by demonstrating high-rate high-efficiency free space optical communications (FSOC) between a satellite orbiting the moon and a terrestrial ground terminal. Now NASA is developing an operational capability with their Laser Communication Relay Demonstration (LCRD), a geosynchronous (GEO) relay satellite system designed to support terrestrial, airborne and low Earth orbit (LEO) users. LCRD forms the basis for a new next-generation relay capable of ten to 100 times higher data volumes with lightweight and low-power optical terminals. The Multi-rate Differential Phase Shift Keying (DPSK) Optical Communication modem developed by MIT Lincoln Laboratory provides the FSOC technology base for NASA’s next-generation near-Earth satellite communications capability and forms the basis for the United States’ first FSOC satellite communications standard, which is under development with the International Consultative Committee for Space Data Systems (CCSDS) standards body today. With its use of narrow beams and plentiful optical electromagnetic spectrum, FSOC is an enabling technology that can provide power-efficient, high-speed communications over long distances. With desirable sensitivity, speed, and relatively low-complexity implementation, DPSK has become an attractive candidate for future spacebased FSOC systems.