The Optical and Quantum Communication Group develops impactful quantum and classical technologies and system prototypes for use in a wide range of challenging applications in terrestrial, space and underwater environments. Primary areas of research include the development of novel entangled-photon source technologies and quantum memory systems; novel quantum link architectures; sensitive single-photon receivers; novel modulation and coding approaches; multi-format laser-comm modems; robust and compact free-space optical beam directors; and precision beam pointing, link acquisition and tracking systems. The group is leveraging these technologies for use in prototype systems that are deployed in the field to inform next-generation quantum and classical optical system capabilities. Examples of near-term field tests include terabit-per-second direct-to-Earth small-satellite constellations, near-Earth wideband relay laser communication terminal hardware for space and ground terminal use, ...