Modulated Entangled Photon Source for Quantum Secret Sharing

Passive entangled photon sources, in which only one state is optimized for are suitable for two-party quantum key distribution (QKD). However, quantum based protocols that involve more participants require a more flexible photon source. In particular, quantum secret sharing (QSS) can be implemented using two-photon states only, whereby the source acts as an active participant [1].