Multi-client quantum key distribution using wavelength division multiplexing

Abstract

Quantum Key Distribution (QKD) exploits the rules of quantum mechanics to generate and securely distribute a random sequence of bits to two spatially separated clients. Typically a QKD system can support only a single pair of clients at a time, and so a separate quantum link is required for every pair of users. We overcome this limitation with the design and characterization of a multi-client entangled-photon QKD system with the capacity for up to 100 clients simultaneously. The time-bin entangled QKD system includes a broadband down-conversion source with two unique features that enable the multi-user capability. First, the photons are emitted across a very large portion of the telecom spectrum. Second, and more importantly, the photons are strongly correlated in their energy degree of freedom. Using standard wavelength division multiplexing (WDM) hardware, the photons can be routed to different parties on a quantum communication network, while the strong spectral correlations ensure that each client is "linked" only to the client receiving the conjugate wavelength. In this way, a single down-conversion source can support dozens of channels simultaneously--and to the extent that the WDM hardware can send different spectral channels to different clients, the system can support multiple client pairings. We will describe the design and characterization of the down-conversion source, as well as the client stations, which must be tunable across the emission spectrum.

Mutual entity authentication of a quantum key distribution network system using authentication qubits

“…exploring network architectures [10][11][12][13][14][15][16][17][18][19][20][21], and performing security analyses [22][23][24][25][26].…”

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

“…Setups using dense wavelength division multiplexing (DWDM) for the distribution of polarization-entangled photons via optical fibers have been realized for photons generated by spontaneous parametric down-conversion (SPDC) in periodically poled fibers [17] or crystals [18][19][20]. Distribution of polarization-entangled photon pairs has been successfully implemented over submarine fibers [21,22] and was the basis for a demonstration of a city-scale QKD network with eight users based on polarization coding [15].…”

Round-robin-differential-phase-shift quantum key distribution based on wavelength division multiplexing

“…Wavelength division multiplexing (WDM) [16,17] has been widely applied in optical fibre QKD communication [18][19][20][21][22][23]. The WDM technology has many mature implementations.…”