An entanglement-based quantum network based on symmetric dispersive optics quantum key distribution

Abstract

Quantum key distribution (QKD) is a crucial technology for information security in the future. Developing simple and efficient ways to establish QKD among multiple users is important to extend the applications of QKD in communication networks. Herein, we proposed a scheme of symmetric dispersive optics QKD and demonstrated an entanglement-based quantum network based on it. In the experiment, a broadband entangled photon pair source was shared by end users via wavelength and space division multiplexing. The wide spectrum of generated entangled photon pairs was divided into 16 combinations of frequency-conjugate channels. Photon pairs in each channel combination supported a fully connected subnet with eight users by a passive beam splitter. Eventually, it showed that an entanglement-based QKD network over 100 users could be supported by one entangled photon pair source in this architecture. It has great potential on applications of local quantum networks with large user number.

Fully Connected Entanglement-based Quantum Communication Network without Trusted Node

“…Only one quantum light source was required, and it should provide multiple entanglement sources by wavelength division multiplexing. The quantum light source can be realized using several methods, such as spontaneous parametric down conversion in PPLN crystals 34 , waveguides 40 , PPKTP 41 , poled fiber 42,43 , and SFWM in silicon waveguides 36 . The bandwidth of the quantum light source determines the quantity of entanglement resources that can be provided, and hence the number of users that can be supported by this network architecture.…”

“…In each user, a normal dispersion component, an anomalous dispersion component, and two NbN superconducting nanowire single-photon detectors (SNSPDs) were equipped for performing symmetric dispersive optics QKD (DO-QKD) 36 . The symmetric DO-QKD was modified from the conventional DO-QKD scheme [37][38][39] to fully adapt to the entanglement distribution network based on passive beam splitters.…”

“…However, it can be further improved. Recently, another type of fully connected quantum network was proposed 36 . In this scheme, resources of entangled photon pairs occupied with two correlated wavelength channels were directly distributed to eight users by a passive beam splitter to construct a fully connected subnet.…”

A scalable network for simultaneous pairwise quantum key distribution via entanglement-based time-bin coding

“…Wavelength-division multiplexing schemes as presented in [15,20] could be used to implement fully-connected networks with our setup, since they also use type-0 SPDC photon sources. Moreover, in combination with active or passive time multiplexing, networks with participants grouped in fully connected subnetworks can be realized [38,45]. An alternative to such schemes with a fixed channel allocation is to allocate the bandwidth dynamically based on key rate demand with a wavelength-selective switch as demonstrated for entanglement-based QKD [46].…”

A two-way photonic quantum entanglement transfer interface

“…Different from polarization entanglement which requires real-time active control to compensate polarization drifts [14][15][16][17], timeenergy entanglement, both continuous and discrete versions, shows intrinsic robustness for propagation through long-distance fiber with the help of passive dispersioncompensating devices [18,19]. To date, time-energy entanglement sources have been widely used in optical-fiber quantum tasks, such as quantum key distribution [20][21][22], dense coding [23] and long-distance quantum entanglement swapping [24]. It is an important candidate for building long-distance optical fiber networks.…”