Polarization discriminated time‐bin phase‐encoding measurement‐device‐independent quantum key distribution

Abstract

The correctness of measurement-device-independent quantum key distribution (MDI-QKD) has been demonstrated in tremendous amount of researches. There is an interesting proposal which can collect all coincidences by transforming two pairs of orthogonal polarization states into the encoding states of MDI-QKD. The attempt is meaningful. Here, based on this proposal, we realize a proof-of-principle demonstration. Only one phase modulator is applied to encode the qubits. The phase-reference-frame is aligned by modulating the phase modulator of the phase modulation unit. We modulate the signals into three intensities, and a secure key rate of bits per pulse is successfully demonstrated. Our experimental system simplifies the encoding process and has the potential to implement the reference-frame-independent MDI-QKD protocol.