Measurement-device-independent quantum key distribution based on postprocessing time-domain filtering
Phys. Rev. Applied 25, 054032 – Published 13 May, 2026
DOI: https://doi.org/10.1103/gvvj-17xy
Abstract
Measurement-device-independent quantum key distribution (MDI-QKD) eliminates all detector-side vulnerabilities. Compared to weak coherent pulses, heralded single-photon sources (HSPSs) signal the presence of photons, thereby extending the achievable distance of MDI-QKD and enabling advanced protocols such as passive decoy-state implementations and quantum-memory-assisted configurations. In practice, however, spectral correlations between photon pairs in HSPS degrade Hong-Ou-Mandel (HOM) interference visibility. Although narrowband filtering can suppress this effect, it relies on dedicated hardware and lacks flexibility. Here, we propose an MDI-QKD scheme based on a time-domain postprocessing filtering technique that requires no additional hardware, significantly improving both the key rate and the maximum transmission distance. By optimizing the filter width, this method flexibly adapts to variations in the source or channel. Furthermore, it can be readily extended to other protocols relying on HOM interference, including quantum teleportation and entanglement swapping.
Physics Subject Headings (PhySH)
Corrections
1 June, 2026
Correction: The email address given in the contact author footnote was incorrect and has been fixed.
