Design of a ground-based optical receiver for the lunar laser communications demonstration

In this paper we present a design for a photon-counting optical receiver-based on superconducting NbN nanowire detector arrays-that will be employed in the ground terminal for the NASA Lunar Laser Communications Demonstration. The ground receiver is designed with four, 40 cm apertures, each coupled to a novel multi-mode polarization-maintaining fiber. The receiver is designed to receive a variable-rate pulse-position-modulated signal with a maximum data rate of 622 Mb/s.