Geiger-Mode SiGe Receiver for Long-Range Optical Communications

In this program, Freedom Photonics proposes to develop a photon-counting detector array, sensitive in the 1550 nm wavelength range, suitable for Free-Space-Optical (FSO) communications where high data rates from space missions are critical, such as the Lunar Laser Communication Demonstration (LLCD). The proposed photodetector array is akin to the well known Silicon Photomultiplier (SiPM) but using the SiGeSn ternary alloy, rather than just Si, to extend the detection wavelength range to 1550 nm. To our knowledge, no such solid state "photomultiplier" device exists currently for detection at 1550 nm. This SiGeSn Semiconductor Photomultiplier (SPM) will be epitaxially grown on a CMOS wafer, so that it will include monolithically integrated time tagging electronics for a significant reduction in Size, Weight and Power (SWaP), compared to current state-of-the-art lasercom receivers. Potential NASA customers for these products include: o Space Technology Directorate o Science Directorate o Human Exploration and Operations Directorate o Deep Space Optical Communications (DSOC) o Laser Communications Relay Demonstration (LCRD) o Space Network (SN) o Near Earth Network (NEN) o Lunar Laser Communication Demonstration (LLCD) o International Space Station o New Horizons: Pluto and Beyond

Potential applications for the FSO high sensitivity photodetector include: - Space communications - Aircraft-to-aircraft and aircraft-to-ground communications - Communication links for internet-by-balloon or internet-by-drone as currently being developed by Google and Facebook - Building-to-building connectivity, where the improved detector sensitivity would improve performance under some adverse weather conditions Customers for these products include: Other Government o Department of Defense o Department of Agriculture o Department of Homeland Security o Department of Energy Non-Government Commercial o Companies developing aerial internet distribution such as Google and Facebook o Space exploration companies such as SpaceX and Orbital ATK o FSO link manufacturing companies such as fSona and Lightpointe More »