A long-lived spectrally multiplexed solid-state optical quantum memory for high-rate quantum repeaters

Long optical storage times are an essential requirement to establish high-rate entanglement distribution over large distances using memory-based quantum repeaters. Rare earth ion-doped crystals are arguably well-suited candidates for building such quantum memories. Toward this end, we investigate the 795.32 nm ³H₆ ↔ <sup...

Measurement of the thulium ion spin Hamiltonian in an yttrium gallium garnet host crystal

We characterize the magnetic properties for thulium ion energy levels in the (Tm:YGG) lattice with the goal to improve decoherence and reduce linewidth broadening caused by local host spins and crystal imperfections. More precisely, we measure hyperfine tensors for the lowest level of and excited states using a combination of spectral hole...

Long-Lived Solid-State Optical Memory for High-Rate Quantum Repeaters

We argue that long optical storage times are required to establish entanglement at high rates over large distances using memory-based quantum repeaters. Triggered by this conclusion, we investigate the 795.325 nm3 H6↔H34 transition of Tm:Y3Ga5O12 (Tm:YGG). Most importantly, we find that the optical coherence time can reach 1.1 ms, and, using...

Entanglement distribution in multi-platform buffered-router-assisted frequency-multiplexed automated repeater chains

Realization of a globe-spanning quantum network is a current worldwide goal, where near and long term implementations will benefit from connectivity between platforms optimized for specific tasks. Towards this goal, a quantum network architecture is herewith proposed whereby quantum processing devices based on NV- colour centers act as...

Proposal and proof-of-principle demonstration of fast-switching broadband frequency shifting for a frequency-multiplexed quantum repeater

A proposal for fast-switching broadband frequency-shifting technology making use of frequency conversion in a nonlinear crystal is set forth, whereby the shifting is imparted to the converted photons by creating a bank of frequency-displaced pump modes that can be selected by a photonic switch and directed to the nonlinear crystal. Proof-of...

Persistent atomic frequency comb based on Zeeman sub-levels of an erbium-doped crystal waveguide

Long-lived sub-levels of the electronic ground-state manifold of rare-earth ions in crystals can be used as atomic population reservoirs for photon echo-based quantum memories. We measure the dynamics of the Zeeman sublevels of erbium ions that are doped into a lithium niobate waveguide, finding population lifetimes at cryogenic temperatures...

Entanglement and nonlocality between disparate solid-state quantum memories mediated by photons

Entangling quantum systems with different characteristics through the exchange of photons is a prerequisite for building future quantum networks. Proving the presence of entanglement between quantum memories for light working at different wavelengths furthers this goal. Here, we report on a series of experiments with a thulium-doped crystal,...

Telecom-wavelength quantum memories in rare earth ion-doped materials for quantum repeaters

The quantum internet, when finally deployed, will enable a plethora of new applications such as theoretically proven secure communication and networked quantum computing, much the same as its classical counterpart whose development began back in the 1990’s. The task of creating a globe-spanning quantum network, however, is proving a rather...

Storage and Reemission of Heralded Telecommunication-Wavelength Photons Using a Crystal Waveguide

Large-scale fiber-based quantum networks will likely employ telecommunication-wavelength photons of around 1550 nm wavelength to exchange quantum information between remote nodes, and quantum memories, ideally operating at the same wavelength, that allow the transmission distances to be increased, as key elements of a quantum repeater....