Transmission of photonic polarization states from geosynchronous Earth orbit satellite to the ground

Abstract

Geosynchronous Earth orbit (GEO) satellites can extend the transmission distance of the quantum states and the intercrossing time between the satellites and the ground, which will greatly promote the application spatial scale of quantum communications. In this work we report the first experimental test of transmission of photonic polarization states from a GEO SJ-20 satellite at more than 36,000 km distance to the Li-jiang ground station at Yun-nan Observatory. The test equipment carried on the satellite can send four kinds of photonic polarization states at 50 MHz pulse frequency. A 1.76 m telescope and related optical system in the ground station are used to receive the photonic polarization states, and then these polarization states are probed by the superconducting nanowire single photon detector. The test results show that the optical attenuation between the GEO satellite and the ground station is 100 ˜ 110 dB and the channel bit error rate is 2%–8%, which meet the security criteria of quantum key distribution and quantum secure direct communication.