Is there a fundamental limit on the length of a communication channel in a single-photon quantum cryptosystem?
S. N. Molotkov, S. S. Nazin · Journal of Experimental and Theoretical Physics Letters · 1996
It is shown that there is no formal limit on the length of the communication channel in a single-photon quantum cryptosystem with arbitrary dispersion if there is no damping in the communication line. A prescription is given for finding a signal shape such that the total duration of the signal at the entrance and exit of the communication channel can be made arbitrarily small. Such a signal is in a certain sense optimal.