Field implementation of long-distance quantum key distribution over aerial fiber with fast polarization feedback

Abstract

Quantum key distribution with polarized qubits has not yet been realized over the aerial fiber, due to rapid polarization changes. Here, we report our recent work towards quantum communication through an aerial fiber channel. We designed a fast polarization feedback module featuring high efficiency, fast speed, and good stability. With this module, we implemented long-distance quantum key distribution over different types of aerial fiber links based on polarization encoding. Our work takes a significant step towards the application of quantum communications in complex environments.

Simple quantum key distribution with qubit-based synchronization and a self-compensating polarization encoder

“…Polarization-encoded QKD in fiber-optic links has been studied to great extent, mainly encouraged by the simplicity of the receiver, which can be completely passive and requires only standard components [21,23,26,27]. Unfortunately, this type of link has an important drawback given by the natural birefringence of optical fibers, which causes the polarization state of transmitted photons to change continuously and in an unpredictable fashion [28].…”

Performance Analysis of Quantum Key Distribution Technology for Power Business

“…The aerial part extends for 98.88 km, with the attenuation of 31.3 dB. The key negotiation between transmitter and receiver based on decoy-state BB84 QKD protocol [29]. The wavelength of quantum signals was 1550 nm.…”

“…At the business layer, the choice of encryption algorithm can affect the interactive performance of power services. Combined with the test results under power overhead cable environment, a fast polarization feedback algorithm has been proposed to improve the performance of QKD [29,30]. This algorithm utilizes wavelength division multiplexing technology to achieve both strong and weak light fiber transmission.…”

Fibre polarization state compensation in entanglement-based quantum key distribution

“…This pair of reference signals needs to be prepared into two non-orthogonal polarization states, and the polarisation controller then is adjusted to reach a configuration where it restores the states of both reference signals at the output of the fibre. The reference signals can co-exist with the QKD photons in the same fibre via either time-division or wavelength-division multiplexing [20][21][22]. This type of compensation can operate at a high bandwidth at the cost of increasing hardware complexity, and is suitable for QKD systems with rapidly-oscillating environmental noise [22].…”

“…The reference signals can co-exist with the QKD photons in the same fibre via either time-division or wavelength-division multiplexing [20][21][22]. This type of compensation can operate at a high bandwidth at the cost of increasing hardware complexity, and is suitable for QKD systems with rapidly-oscillating environmental noise [22].…”