Experimental Design and Performance Simulation of Core Components for BBM92 Entanglement-Based Quantum Key Distribution
Entanglement-based quantum key distribution (QKD) offers robust key distribution through intrinsically correlated measurements, ensuring that any eavesdropping attempt introduces detectable disturbances. Although practical implementations are primarily limited to fixed fiber networks, extending QKD to mobile platforms like drones or small satellites introduces challenges in optical alignment, weight, and power consumption. This work outlines the core components and architecture for implementing BBM92-based QKD in mobile settings. A compact polarization Sagnac interferometer that utilizes a periodically poled potassium titanyl phosphate crystal provides a stable and efficient method for generating entangled photon pairs. The supporting subsystems include a polarization compensation system, detector module, and an acquisition, pointing, and tracking (APT) system. To assess performance under realistic conditions, we simulate photon loss, detector efficiency, and quantum bit error rates (QBERs) using the Simulator for Quantum Networks and Channels framework. The results show an average key generation rate of 5.43 bits/s, a final secure key length of 45.27 bits per block, and a QBER of 4.5%.