title: Multi-aperture digital coherent combining for free-space optical communication receivers.
abstract: Space-to-ground optical communication systems can benefit from reducing the size, weight, and power profiles of space terminals. One way of reducing the required power-aperture product on a space platform is to implement effective, but costly, single-aperture ground terminals with large collection areas. In contrast, we present a ground terminal receiver architecture in which many small less-expensive apertures are efficiently combined to create a large effective aperture while maintaining excellent receiver sensitivity. This is accomplished via coherent detection behind each aperture followed by digitization. The digitized signals are then combined in a digital signal processing chain. Experimental results demonstrate lossless coherent combining of four lasercom signals, at power levels below 0.1 photons/bit/aperture.
authors.forename: David J
authors.initials: DJ
authors.lastname: Geisler
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Yarnall
authors.forename: Mark L
authors.initials: ML
authors.lastname: Stevens
authors.forename: Curt M
authors.initials: CM
authors.lastname: Schieler
authors.forename: Bryan S
authors.initials: BS
authors.lastname: Robinson
authors.forename: Scott A
authors.initials: SA
authors.lastname: Hamilton