Long range laser optical communications offer advantages of higher bandwidth and better accuracy over RF communications. NASA has demonstrated higher bandwidth data transmission using laser optical communication links. Recently, MIT-LL designed and delivered high sensitive Geiger-mode avalanche photodiode (Gm-APD) array receiver as a flight unit for the NASA's deep space communication demonstration program. This will be a first successful demonstration of a Gm-APD receiver technology in space. For many future missions, improvement in detection efficiency, radiation hardness, larger format and space qualifiable Gm-APD photon counting array receivers are needed. We propose a space qualifiable 1064 nm InGaAsP Gm-APD photon counting array receiver with improved photon detection efficiency (PDE). PDE will be improved by increasing the quantum efficiency using reflective layers and increasing the carrier avalanche probability. Our mesa design with a proprietary passivation process offers low dark count rates and improved radiation hardness, In Phase I we plan to demonstrate a 1064 nm InGaAsP Gm-APD photon counting array sensor chip assembly using high detection efficiency arrays. Furthermore, working with NASA, we will establish requirements for a space qualifiable receiver array. The successful completion of Phase I will demonstrate the technical feasibility of a photon counting array receiver with improved sensitivity. In Phase II, we will design, build, and demonstrate a radiation hard 32 x 32 photon counting array receiver with improved sensitivity. We will conduct radiation tests to demonstrate improved radiation hardness. We will deliver an engineering development unit to NASA for evaluation. In addition, we will deliver a flight ready receiver design that will meet specifications for a space mission. Anticipated Benefits NASA applications include deep space optical communications missions, future space missions to earth's moon, Mars, and humans to Mars. Other potential applications include LIDAR for entry, descent, and landing sensor systems, autonomous rendezvous and proximity operations. There has been considerable interest in military and commercial space LaserComm applications. Potential military applications include tracking and identification of hypersonic missiles, beam control sensors for high power laser weapons, vibrometry, direct detection LADAR, and synthetic aperture LADAR.
