Inter-Symbol-Interference Reduction in Continuous Variable QKD Using Equalization

Inter-symbol-interference (ISI) noise in Continuous Variable Quantum Key Distribution (CVQKD) is caused by the overlap between the consecutive detected signals. In practice, this problem limits the repetition rate of the quantum signals for a given bandwidth detector and hence reduces the rate of secure key generation. We propose a method of using equalization to mitigate ISI noise in CVQKD systems. Its feasibility is studied using an analytical model with practical parameters. The improved performance of CVQKD detection is investigated using secure key analysis. The simulation results show an increase of 12.8 Mbits/s in secure key rate for a 1GHz bandwidth CVQKD system operating over a 20 km link.