Multifunctional on-chip storage at telecommunication wavelength for quantum networks

Abstract

Quantum networks will enable a variety of applications, from secure communication and precision measurements to distributed quantum computing. Storing photonic qubits and controlling their frequency, bandwidth, and retrieval time are important functionalities in future optical quantum networks. Here we demonstrate these functions using an ensemble of erbium ions in yttrium orthosilicate coupled to a silicon photonic resonator and controlled via on-chip electrodes. Light in the telecommunication C-band is stored, manipulated, and retrieved using a dynamic atomic frequency comb protocol controlled by linear DC Stark shifts of the ion ensemble’s transition frequencies. We demonstrate memory time control in a digital fashion in increments of 50 ns, frequency shifting by more than a pulse width ( ± 39 M H z ), and a bandwidth increase by a factor of 3, from 6 to 18 MHz. Using on-chip electrodes, electric fields as high as 3 kV/cm were achieved with a low applied bias of 5 V, making this an appealing platform for rare-earth ions, which experience Stark shifts of the order of 10 kHz/(V/cm).

On-Demand Quantum Storage of Photonic Qubits in an On-Chip Waveguide

“…The stark coefficient is calculated as 11.68±0.24 kHz/(V/cm) which is consistent with the result reported in Ref. [21].…”

2022 Roadmap on integrated quantum photonics

“…Ideally, quantum repeaters, which involve quantum memories, can be used for extending the distance. Research efforts are underway toward on-chip quantum memories [263] but several challenges will need to be addressed for such components to be sufficiently mature for use within advanced quantum cryptographic systems. Such systems also rely, for instance, on entangled-photon generation and frequency conversion, where photonic integration has considerably advanced.…”

Integrated Quantum Nanophotonics with Solution‐Processed Materials

“…[229,230] In addition, REI-doped crystals are naturally compatible with integrated nanophotonics as demonstrated recently. [40,219,220,[231][232][233][234] Triply ionized REIs (e.g., Yb 3+ and Er 3+ ) have a partially filled 4f shell that is shielded from the external environment by filled 5s 2 and 5p 6 shells, and the dipole-forbidden 4f-4f transitions of the free ion span a broad range of frequencies from ultraviolet to infrared. Doping a host crystal with REIs splits the degeneracy of the free ion's states, resulting in a manifold of 4f states.…”

“…c) SEM of a silicon optical cavity evanescently coupled to underlying Er 3+ doped YOV and temporal control of optical quantum memory read-out. Blue pulses indicate on-demand memory read-out [231]. d) Photoluminescence spectrum of Yb 3+ CsPbBr 3 perovskite nanocrystals at 5 K and a schematic of Yb 3+ energy level splitting due to the perovskite on-site D 2h symmetry [242].…”