Speaker
Description
Quantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum tolerable loss. Semiconductor quantum dots (QDs) are a promising building block for quantum communication applications because of the deterministic emission of single photons with high brightness and low multiphoton contribution.
In a recent work we have reported on the first intercity QKD experiment using a bright deterministic single photon source. A BB84 protocol based on static polarisation encoding has been realised using the high-rate single photons in the telecommunication C-band emitted from a semiconductor QD embedded in a circular Bragg grating structure [1]. Here we present the high-speed modulation of the polarisation states of telecom C-band single photons. A sequence of 32-bit digital pseudo-random numbers is repeatedly encoded into the polarisation via the interferometer for proof-of-concept purposes. An ultra-low quantum bit error rate compared to existing actively modulated single-photon based QKD is identified using such a configuration.
[1] J. Yang et al., Light Sci. Appl. 13, 150 (2024)
