Satellite-to-ground quantum communication using a 50-kg-class micro-satellite

TL;DR

This paper demonstrates a successful quantum communication experiment between a small micro-satellite and ground station, showing the feasibility of space-based quantum key distribution with low error rates.

Contribution

First implementation of satellite-to-ground quantum communication using a 50-kg-class micro-satellite, enabling secure quantum links from space.

Findings

Quantum communication achieved with a 50-kg micro-satellite in low earth orbit.

Quantum bit error rate below 5%, demonstrating secure communication feasibility.

Successful polarization state transmission and synchronization despite Doppler shifts.

Abstract

Recent rapid growth in the number of satellite-constellation programs for remote sensing and communications, thanks to the availability of small-size and low-cost satellites, provides impetus for high capacity laser communication (lasercom) in space. Quantum communication can enhance the overall performance of lasercom, and also enables intrinsically hack-proof secure communication known as Quantum Key Distribution (QKD). Here, we report a quantum communication experiment between a micro-satellite (48 kg and 50 cm cube) in a low earth orbit and a ground station with single-photon counters. Non-orthogonal polarization states were transmitted from the satellite at a 10-MHz repetition rate. On the ground, by post-processing the received quantum states at an average of 0.14 photons/pulse, clock data recovery and polarization reference-frame synchronization were successfully done even under remarkable Doppler shifts. A quantum bit error rate below 5% was measured, demonstrating the feasibility of quantum communication in a real scenario from space.