Microwave photonic filtering scheme for BB84 Subcarrier Multiplexed Quantum Key Distribution

A high performance microwave photonic filter stage is designed and experimentally tested for the implementation of a BB84 Subcarrier Multiplexed Quantum Key Distribution systems SCM-QKD. Results both in the classical and quantum regime show the feasibility of SCM-QKD obtaining visibility values at least 98 % as required for the successful operation of these systems.