Quantum key distribution using a triggered quantum dot source emitting near 1.3 microns

TL;DR

This paper demonstrates secure quantum key distribution over 35 km of optical fiber using a triggered quantum dot source emitting near 1.3 microns, showing advantages over traditional weak coherent pulses.

Contribution

It introduces a quantum dot source emitting near 1.3 microns for QKD, achieving reduced multiphoton emission and improved transmission distance in fiber optic communication.

Findings

Successful distribution of cryptographic keys over 35 km fiber

Suppression of multiphoton emission to 10% of Poissonian level

Transmission distance exceeds that of optimized weak coherent pulses

Abstract

We report the distribution of a cryptographic key, secure from photon number splitting attacks, over 35 km of optical fiber using single photons from an InAs quantum dot emitting ~1.3 microns in a pillar microcavity. Using below GaAs-bandgap optical excitation, we demonstrate suppression of multiphoton emission to 10% of the Poissonian level without detector dark count subtraction. The source is incorporated into a phase encoded interferometric scheme implementing the BB84 protocol for key distribution over standard telecommunication optical fiber. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310 nm in the same system.