Extremely low power quantum optical communication link for miniature planetary sensor stations

In this paper a very low power optical communications system is addressed that could be developed specifically for creating networks involving a planetary lander and fixed or mobile sensor stations that could be as small as 1 cm 3. The communication system is a variant of photon-counting based communications. Instead of counting individual photons, the system only counts the arrival of time coincident sets of photons. Using sets of photons significantly decreases the bit error rate because they are highly identifiable in the presence of ambient light. An experiment demonstrating reliable communication over a distance of 70 m using less than a billionth of a watt of radiated power is presented. The experiment also compares this technique to traditional photon counting and successfully demonstrates that time coincident photon communications can achieve an equivalent bit error rate at a signal-to-noise ratio that is 5 to 7 dB lower than what is needed for classical photon counting communication. The components used in this system were chosen so that they could in the future be integrated into a cubic centimeter device.