2022 Roadmap on integrated quantum photonics

Abstract

Integrated photonics will play a key role in quantum systems as they grow from few-qubit prototypes to tens of thousands of qubits. The underlying optical quantum technologies can only be realized through the integration of these components onto quantum photonic integrated circuits (QPICs) with accompanying electronics. In the last decade, remarkable advances in quantum photonic integration have enabled table-top experiments to be scaled down to prototype chips with improvements in efficiency, robustness, and key performance metrics. These advances have enabled integrated quantum photonic technologies combining up to 650 optical and electrical components onto a single chip that are capable of programmable quantum information processing, chip-to-chip networking, hybrid quantum system integration, and high-speed communications. In this roadmap article, we highlight the status, current and future challenges, and emerging technologies in several key research areas in integrated quantum photonics, including photonic platforms, quantum and classical light sources, quantum frequency conversion, integrated detectors, and applications in computing, communications, and sensing. With advances in materials, photonic design architectures, fabrication and integration processes, packaging, and testing and benchmarking, in the next decade we can expect a transition from single- and few-function prototypes to large-scale integration of multi-functional and reconfigurable devices that will have a transformative impact on quantum information science and engineering.

Design Methodologies for Integrated Quantum Frequency Processors

“…While we have focused on silicon as an integrated photonic platform, our procedures are general, and may be readily extended to other promising photonic materials including III-V semiconductors, silicon carbide, and thin-film lithium niobate [63]. Indeed, the exceptional efficiency and speed of electro-optic modulators in some of these materialsparticularly lithium niobate [42]-suggests that platforms other than silicon may ultimately prove better suited to the demands of the integrated QFP anyway.…”

Mode mapping Q > 500 000 photonic crystal nanocavities using free carrier absorption

“…Photonic crystals (PhC) have raised interest from fundamental research [1,2], due to their enhanced lightmatter interaction, but maybe even more so from the field of optical signal processing and computing [3,4]. They are prime candidates for optical integrated-circuit applications [5][6][7]. One reason for this is the possibility to design a defect on the PhC platform, creating a PhC resonator (PhCR) that typically has small mode volume and high quality factor (Q) [8] which maximizes the optical nonlinearity crucial to active photonic devices.…”

Current crowding in nanoscale superconductors within the Ginzburg-Landau model

“…Due to their outstanding performance in terms of detection efficiency, time resolution and low intrinsic dark count rates, superconducting nanowire single-photon detectors (SNSPDs) have found wide-spread applications in, for instance, quantum optics, light detection and ranging (LIDAR), biological imaging and astronomy [2][3][4]. Furthermore, SNSPDs can be embedded in photonic integrated circuits [5,6], which allows for miniaturized implementations of complex quantum information processing architectures. In general, the detection mechanism of SNSPDs [7] relies on operating the device relatively close to its critical current to enable the transduction of single photon absorption events into an electrical signal at high quantum efficiency.…”