2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/118431Most traditional applications of quantum cryptography are point-to-point communications, in which only two users can exchange keys. In this letter, we present a network scheme that enable quantum key distribution between multi-user with wavelength addressing. Considering the current state of wavelength division multiplexing technique, dozens or hundreds of users can be connected to such a network and directly exchange keys with each other. With the scheme, a 4-user demonstration network was built up and key exchanges were performed.11 pages, 3 figuresQuantum Physicstext