Photonic Hardware and Network Architectures for the Quantum Internet: From Entanglement Generation to Global Connectivity
The rapid growth of global data traffic and the increasing demand for secure and scalable communication are driving the need for networking paradigms beyond the classical internet. The quantum internet has emerged as a promising solution, leveraging the principles of quantum mechanics to enable intrinsically secure communication, and computation. In this paper, we present a comprehensive review of the fundamental building blocks and system architectures required for large‐scale quantum networks, with a particular focus on photonic hardware platforms. We introduce key concepts of quantum information relevant to networking, including qubits, entanglement, and decoherence, and examine enabling technologies across different qubit platforms, highlighting photonic qubits as the primary carriers for long‐distance communication. We review major deterministic and probabilistic entanglement generation techniques, and analyze entanglement distribution strategies based on fiber, satellite, and quantum repeater architectures. Beyond the physical layer, we provide a system‐level perspective on quantum networking through protocol stack design, as well as challenges in entanglement routing, forwarding, and scheduling. Finally, we discuss experimental testbeds for entanglement distribution in both fiber‐based and free‐space systems, and outline the corresponding challenges and future research directions, including satellite‐assisted architectures for achieving scalable and globally connected quantum networks.