Simulation and design of quantum key distribution systems

Abstract

Previously, we reported a framework capable of simulating classical transmission systems and QKD based on weak-coherent prepare-and-measure protocols. The framework’s modular architecture provides a rich library of models for various system components (e.g., lasers, modulators, fibers). QKD components include singlephoton detectors, transmitter- and receiver designs, and performance estimators. For realistic system designs, component models can account for various imperfections (e.g., laser model with linewidth, RIN, side modes). Here, we present further developments of the framework and its applications. We applied our simulation tool to investigate a satellite-based BB84 system in the downlink scenario. For fiber-based applications in a coexistence scenario, we studied the usage of multicore fibers to better separate classical and quantum channels, and various PON configurations. The system performance was estimated by analyzing the QBER dependence on the classical channel power due to Raman scattering. Furthermore, we discuss the simulation results of a Gaussian-modulated CV-QKD system with a realistic model of a true local oscillator. We studied how the utilization of DSP techniques improves the system’s performance. We evaluated the secret key rate for different transmission distances.