Measurement-device-independent quantum key distribution (MDI-QKD) can solve the detector loophole in traditional QKD protocols, significantly improving the security. It is also easy to extend point-to-point QKD to star-type networks. In recent years, MDI-QKD and its network implementation have become a hot topic in researches of quantum cryptography. In this work, we proposed a scheme of Bell state measurement (BSM) of frequency-nondegenerate photons based on a frequency-domain beam splitter (FBS) and applied it to MDI-QKD. We demonstrated the secure key generation performance of the MDI-QKD of frequency-nondegenerate photons. We also showed that the frequencies of the FBS and the user lasers can be calibrated by the quantum interference measurement at the middle node. This work showed that the MDI-QKD of frequency-nondegenerate photons simplifies the implementation of MDI-QKD and has great potential for realizing wavelength division multiplexing MDI-QKD networks.

This work has been accepted by Physical Review Applied (Volume 17, Eid 024045; https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.17.024045; DOI: 10.1103/PhysRevApplied.17.024045) and online published at 16th Feb. 2022. The first author of this paper is Ph.D. candidate Rong Xue. The corresponding author of this paper is Prof. Wei Zhang.