Polarization-Basis Tracking Scheme in Satellite Quantum Key Distribution

Abstract EN

Satellite quantum key distribution is a promising technique that overcomes the limited transmission distance in optical-fiber-based systems.

The polarization tracking technique is one of the key techniques in the satellite quantum key distribution.

With free-space quantum key distribution between an optical ground station and a satellite, the photon polarization state will be changed according to the satellite movement.

To enable polarization based quantum key distribution between mobile terminals, we developed a polarization-basis tracking scheme allowing a common frame of reference to be shared.

It is possible to orient two platforms along a common axis by detecting the reference optical signal only on the receiver side with no prior information about the transmitter's orientation.

We developed a prototype system for free-space quantum key distribution with the polarization-basis tracking scheme.

Polarization tracking performance was 0.092° by conducting quantum key distribution experiments over a 1 km free space between two buildings in a Tokyo suburb.