Two-parameter single-pass plug and play quantum cryptography without adjustment of states in the quantum channel

All known single-pass fiber-based systems of quantum cryptography require a permanent adjustment of the polarization of states at the output of the quantum channel (QC). A fundamentally new implementation of the single-pass system of quantum cryptography is proposed, which does not require adjustment of the polarization at the output of the QC. Compensation for polarization distortions in the QC occurs automatically on the receiving side—the distortions are self-compensating. This result is achieved due to the fact that the receiving side of the system does not contain active polarization sensitive elements—phase modulators, polarization modulators, polarization controllers etc. The solution of the problem is provided by using a special protocol of quantum key distribution, in which non-orthogonality of states from different bases is achieved due to the time shift.