Differential Phase Shift Quantum Key Distribution

Kyo Inoue, Edo Waks, Yoshihisa Yamamoto
2002 Physical Review Letters  
A novel quantum cryptography scheme is proposed, in which a single photon is prepared in a linear superposition state of three basis kets. A photon split to three pulses is sent from Alice to Bob, where the phase difference between sequential two pulses carries bit information. Bob measures the phase difference by passive differential phase detection. This scheme is suitable for fiber transmission systems and offers a key creation efficiency higher than conventional fiber-based BB84.
doi:10.1103/physrevlett.89.037902 pmid:12144419 fatcat:2zjn57fnerdvfnage5rm7kmfzu