Space-Qualifiable Photon-Counting Lasercom receiver

Despite the recent success of LLCD, no NASA laser communication space terminals have a photon-counting optical receiver.  Under prior funding  NASA Goddard Space Flight Center acquired a space-qualifiable photon-counting detector array that uses Mercury Cadmium Telluride (HgCdTe) avalanche photodiodes (APD).  We propose to test this HgCdTe APD detector array in a photon counting receiver that may enable future LEO, GEO, Deep Space and ground lasercom terminals.

The objective of this IRAD is to test the laser communications performance of the HgCdTe APD array so that it’s’ suitability for flight projects is known, i.e. this is a technology maturation effort for risk reduction.  These HgCdTe APD arrays have recently been radiation-tested with acceptable results to allow reliable use for flight missions.   In this IRAD, we propose to use our laser communication transmitter, innovative impairment/penalty testing techniques and software, and test equipment infrastructure to test the communication performance (photons/bit, timing jitter, etc.) of the designated HgCdTe single carrier e-APD array.