Programmable frequency-bin quantum states in a nano-engineered silicon device

Abstract

Photonic qubits should be controllable on-chip and noise-tolerant when transmitted over optical networks for practical applications. Furthermore, qubit sources should be programmable and have high brightness to be useful for quantum algorithms and grant resilience to losses. However, widespread encoding schemes only combine at most two of these properties. Here, we overcome this hurdle by demonstrating a programmable silicon nano-photonic chip generating frequency-bin entangled photons, an encoding scheme compatible with long-range transmission over optical links. The emitted quantum states can be manipulated using existing telecommunication components, including active devices that can be integrated in silicon photonics. As a demonstration, we show our chip can be programmed to generate the four computational basis states, and the four maximally-entangled Bell states, of a two-qubits system. Our device combines all the key properties of on-chip state reconfigurability and dense integration, while ensuring high brightness, fidelity, and purity.

Biphoton spectral quantum interference for information processing and delay metrology

“…Efforts to generate the positively correlated Bell states (|Φ ± ⟩) via spontaneous four-wave mixing by dual spectral-line pumping of microrings in series have also been explored recently. 20…”

Generation of frequency-degenerate photon pairs in a bidirectionally pumped silicon micro-ring resonator

“…These advantages include resonant enhancement, enabling efficient photon pair generation at low pump powers; an innate narrow bandwidth, augmenting the spectral purity and indistinguishability of emitted photons; and a compact footprint, facilitating the integration of multiple sources within a confined area. Consequently, the use of MRRs as sources of single photons has attracted considerable attention and been extensively studied [3][4][5][6][7][8][9] . Large-scale quantum photonic chip requires numerous indistinguishable single photons, and one simple thought is to integrate multiple MRR sources on the chip.…”

Generation of Quantum Optical Frequency Combs in Topological Resonators

“…Due to its multipartite state, the available quantum resource (also referred to as Hilbert space size) scales as $$d^N$$, where d and N denote the number of dimensions and parties, respectively. [ 1 ] Quantum frequency combs show high‐dimensional quantum correction such as energy–time entanglement, [ 10–14 ] frequency‐bin entanglement, [ 15,16 ] and even hyperentanglement. [ 5,17 ] As a result, high‐dimensional entanglement of quantum frequency combs has been proven to boost a range of applications, including quantum communications [ 18 ] and quantum computation.…”