Frequency-multiplexed entanglement for continuous-variable quantum key distribution

Quantum key distribution with continuous variables already uses advantageous high-speed single-mode homodyne detection low electronic noise at room temperature. Together continuous-variable information encoding to nonclassical states, the distance for secure transmission through lossy channels can approach 300 km in current optical fibers. Such protocols tolerate higher channel and also limited data processing efficiency compared coherent-state protocols. The secret rate be further increased by increasing system clock rates, and, further, a suitable frequency-mode-multiplexing of channels. However, multiplexed modes couple together source or any other part protocol. Therefore, communication will experience cross talk gain minuscule. Advantageously, detectors allow solving this cross-talk problem proper processing. It is potential advantage over single-photon detectors, which do not enable similar techniques. We demonstrate positive outcome methodology on experimentally characterized frequency-multiplexed entangled femtosecond pulses natural between eight pairs modes. As main result, we predict almost 15-fold rate. This experimental test analysis entanglement open way field implementation high-capacity quantum variables.