Quantum measurements enable classical/quantum blended networks

Multi-institutional quantum networks that connect nodes at a metropolitan scale are being developed. Those networks face limitations due to the need for synchronous, real-time communication of classical information alongside with quantum channels. Using the same fiber simultaneously for classical and quantum traffic is beneficial but requires additional consideration. Unexpectedly, blending classical and quantum traffic can enhance classical data transmission with quantum features, such as unambiguous security. Additionally, classical information capacity can be dramatically improved by reusing quantum-networking hardware. I will discuss communicating with faint light, significantly weaker than that used for conventional classical communication, yet significantly stronger than that used for quantum communication and quantum key distribution.