Quantum Key Distribution Based on Heralded Pair Coherent State and Orbital Angular Momentum

In order to solve the problem that the quantum key distribution protocol based on the heralded pair coherent state (HPCS) adopts polarization coding and phase coding to bring the basis dependence, a measurement device independent quantum key distribution protocol for asymmetric channels based on the HPCS and orbital angular momentum (OAM) is studied. The relationship among the mean photon number, bit error rate, key generation rate and channel transmission loss of the protocol at different distance ratios is analyzed. The performances of measurement device independent quantum key distribution protocols for symmetric and asymmetric channels with the HPCS and OAM arc compared. The simulation results show that the use of the HPCS compensates for the lack of weak coherent source and heralded single photon source, greatly reducing the vacuum pulse and increasing the single photon pulse. As the channel transmission loss increases, the key generation rate and the secure transmission distance gradually decrease, but the performance of the asymmetric channel is still better than that of the symmetric channel.