Abstract Efficient photon-photon interaction towards 100% efficiency is a longstanding goal in optical quantum information processing, but remains challenging because of weak nonlinearity on current nonlinear optical platforms, or demanding requirements of on-chip microresonators. Here, we propose a scheme for deterministic photon-photon interaction (DPPI) by achieving microresonator phase matching, in an AlGaAs-on-insulator (AlGaAsOI) microdisk resonator. A 2.8 μ m radius microdisk with a full air-cladding structure is used, for minimizing mode volume with low simulated bending loss. Strong structural dispersion engineering can be introduced in such small size, to achieve phase matching between TE and TM fundamental modes for maximal mode overlap. DPPI is therefore predicted with Q of only on the order of 4 × 10 6 , providing a target for future fabrication development on the AlGaAsOI platform. Such scheme accesses the ultra-high material χ (2) coefficient of the III–V material integrated photonic platform, bringing in potential for full-integrated multi-function optical quantum chip towards many quantum information processing tasks.
Abstract Efficient photon-photon interaction towards 100% efficiency is a longstanding goal in optical quantum information processing, but remains challenging because of weak nonlinearity on current nonlinear optical platforms, or demanding requirements of on-chip microresonators. Here, we propose a scheme for deterministic photon-photon interaction (DPPI) by achieving microresonator phase matching, in an AlGaAs-on-insulator (AlGaAsOI) microdisk resonator. A 2.8 μ m radius microdisk with a full air-cladding structure is used, for minimizing mode volume with low simulated bending loss. Strong structural dispersion engineering can be introduced in such small size, to achieve phase matching between TE and TM fundamental modes for maximal mode overlap. DPPI is therefore predicted with Q of only on the order of 4 × 10 6 , providing a target for future fabrication development on the AlGaAsOI platform. Such scheme accesses the ultra-high material χ (2) coefficient of the III–V material integrated photonic platform, bringing in potential for full-integrated multi-function optical quantum chip towards many quantum information processing tasks.
Integrated photonics provides a powerful approach for developing compact, stable and scalable architectures for the generation, manipulation and detection of quantum states of light. To this end, several material platforms are being developed in parallel, each providing its specific assets, and hybridization techniques to combine their strengths are now possible. This review focuses on AlGaAs, a III-V semiconductor platform combining a mature fabrication technology, direct band-gap compliant with electrical injection, low-loss operation, large electro-optic effect, and compatibility with superconducting detectors for on-chip detection. We detail recent implementations of room-temperature sources of quantum light based on the high second- and third-order optical nonlinearities of the material, as well as photonic circuits embedding various functionalities ranging from polarizing beamsplitters to Mach-Zehnder interferometers, modulators and tunable filters. We then present several realizations of quantum state engineering enabled by these recent advances and discuss open perspectives and remaining challenges in the field of integrated quantum photonics with AlGaAs.
The exploration of photonic systems for quantum information processing has generated widespread interest in multiple cutting-edge research fields. Photonic frequency encoding stands out as an especially viable approach, given its natural alignment with established optical communication technologies, including fiber networks and wavelength-division multiplexing systems. Substantial reductions in hardware resources and improvements in quantum performance can be expected by utilizing multiple frequency modes. The integration of nonlinear photonics with microresonators provides a compelling way for generating frequency-correlated photon pairs across discrete spectral modes. Here, by leveraging the high material nonlinearity and low nonlinear loss, we demonstrate an efficient chip-scale multi-wavelength quantum light source based on AlGaAs-on-insulator, featuring a free spectral range of approximately 200 GHz at telecom wavelengths. The optimized submicron waveguide geometry provides both high effective nonlinearity (~550 m−1W−1) and broad generation bandwidth, producing eleven distinct wavelength pairs across a 35.2 nm bandwidth with an average spectral brightness of 2.64 GHz mW−2nm−1. The generation of energy-time entanglement for each pair of frequency modes is verified through Franson interferometry, yielding an average net visibility of 93.1%. With its exceptional optical gain and lasing capabilities, the AlGaAs-on-insulator platform developed here shows outstanding potential for realizing fully integrated, ready-to-deploy quantum photonic systems on chip.
The capability of realizing quantum photonics implementations on-chip will have a strong impact on several aspects of quantum computation and information processing. The implementation of large scale integrated quantum photonic technologies requires on-chip reconfigurable waveguide circuits as well as single-photon sources and detectors. Many successes have been made in recent years to demonstrate complex quantum circuits in many material platforms. Among all these platforms, the Silicon-on-Insulator (SOI) platform is outstanding as it is well developed for classical applications and therefore deploys a high component density, mature fabrication techniques and compatibility with the telecom regime and the complementary metal-oxide-semiconductor (CMOS) technology. However, the lack of on-demand non-classical light sources, directly incorporated in silicon chips, forces the use of nonlinear processes to generate non-classical light states: the probabilistic nature of the emission process sets a limit in the maximally achievable experimental complexity. The use of on-demand sources will have a strong impact on the device’s scalability.
The realization of deterministic photon–photon gates is a central goal in optical quantum computation and engineering. A longstanding challenge is that optical nonlinearities in scalable, room-temperature material platforms are too weak to achieve the required strong coupling, due to the critical loss-confinement trade-off in existing photonic structures. In this work, we introduce a spatio-temporal confinement method, dispersion-engineered temporal trapping, to circumvent the trade-off, enabling a route to all-optical strong coupling. Temporal confinement is imposed by an auxiliary trap pulse via cross-phase modulation, which, combined with the spatial confinement of a waveguide, creates a “flying cavity” that enhances the nonlinear interaction strength by at least an order of magnitude. Numerical simulations confirm that temporal trapping confines the multimode nonlinear dynamics to a single-mode subspace, enabling high-fidelity deterministic quantum gate operations. With realistic dispersion engineering and loss figures, we show that temporally trapped ultrashort pulses could achieve strong coupling on near-term nonlinear nanophotonic platforms. Our results highlight the potential of ultrafast nonlinear optics to become the first scalable, high-bandwidth, and room-temperature platform that achieves strong coupling, opening a path to quantum computing, simulation, and light sources.
The generation of single photons serves as the backbone for tasks in quantum information processing. Generating quantum electromagnetic fields on highly dispersive platforms is technically challenging, though, due to phase-matching constraints. The authors consider the silicon photonic platform, due to its potential scalability, and demonstrate that phase matching is possible with highly dispersive transverse-magnetic polarized light, via nonlinear coupling of two racetrack-style microresonators. With its brightness and tunability, this source may have a significant impact on creation of entangled photons in photonic integrated circuits, for use in quantum information and communication.
Chip-scale integrated photonic circuits provide an attractive platform for the implementation of many quantum photonic technologies ranging from precise metrology to secure communication and quantum computation. In particular, silicon photonic platforms support micron-scale nonlinear optical sources of non-classical light which can be mass manufactured using the robust fabrication processes pioneered by the CMOS microelectronics industry. Integration of these quantum photonic sources with high-performance classical photonic devices on the same chip is required for truly scalable quantum information technologies. Integrated nonlinear resonators are investigated as sources of quantum mechanically correlated photon pair sources. An all-order dispersion engineering method is presented as a robust design synthesis for micoring sources. In addition, a novel concept of coupled mode dispersion compensation is proposed and demonstrated, providing significantly improved performance characteristics of resonant four-wave mixing sources. Next a photon pair source is demonstrated in a commercial CMOS microelectronics process opening the door to future integration of quantum photonics with electronic logic and control circuits. Classical nonlinear optical measurements of stimulated four-wave mixing are used for the first time to accurately predict the quantum correlations from the same device operating in the photon pair regime. Next the first demonstration of fully on-chip pump rejection is demonstrated with over 95 dB pump extinction improving the figures of merit from previous demonstrations by multiple orders of magnitude, including losses, detected pair rates and size. Finally, proposals for introducing novel degrees of freedom provided by an integrated platform are presented for further improving the performance of both photon pair and classical nonlinear optical sources.