Photonic integrated circuits (PICs) based on silicon-on-insulator (SOI) substrates provide a lightweight, compact platform for applications in quantum optics. We show the evaluation and characterization of an SOI-bascd PIC design for an entangled photon pair source, generating photon pairs by means of the nonlinear process of spontaneous four-wave mixing in microring resonators. Experimental results following from the chip fabrication fed back into the simulated parameter tuning effects, culminating in photon pair generation with measured correlations exceeding classically predicted limits.
Photonic integrated circuits (PICs) based on silicon-on-insulator (SOI) substrates provide a lightweight, compact platform for applications in quantum optics. We show the evaluation and characterization of an SOI-bascd PIC design for an entangled photon pair source, generating photon pairs by means of the nonlinear process of spontaneous four-wave mixing in microring resonators. Experimental results following from the chip fabrication fed back into the simulated parameter tuning effects, culminating in photon pair generation with measured correlations exceeding classically predicted limits.
Photon pair sources with the capability to tune the wavelength and correlation properties of the generated photons can be useful for quantum applications such as communication, sensing, and computing. Silicon devices based on the SOI (silicon-on-insulator) platform benefits from both tight modal confinement, due to high index contrast between core and cladding, and CMOS compatible manufacturing process, making it a suitable platform for such sources. In the present work, we discuss the possibility of using planar resonant silicon devices with bend radii of a few tens of microns as photon pair sources. We discuss that a silicon nanophotonic chip consisting of either a single microring or coupled microrings can be used to generate photon pairs around 1.55 um. We discuss that the photons are generated in multiple pairs of wavelengths and can be tuned over several nanometers, demonstrating the capability to generate wavelength division multiplexed photon pairs at freely chosen telecommunication-band wavelengths. Further on, we discuss the ease of control over the bi-photon spectrum of the generated photon pairs and its implication in controlling their correlation properties. Uncorrelated photon pairs can be used to herald a single photon, and correlated photon pairs can be used in various quantum applications such as communication and sensing. In the end, we discuss the design parameters of a single microring resonator based sources.
Compact, efficient, high-quality and scalable non-classical photon sources are one of the most critical building blocks for quantum information processing and communications. Photon pair generation via spontaneous four wave mixing is being recognized as an attractive platform for quantum optics which is compatible with the rapidly-maturing classical integrated photonics technology using silicon wafers, which is adopted in industry for its low cost, high performance and scalability. Traditionally, the photon pairs generated from silicon photonic devices, however, have not compared favorably with traditional nonlinear crystals in terms of overall rate, quality and efficiency. This dissertation discusses the factors that affect the quality and efficiency of photon pair generation in silicon integrated photonic microrings, together with their design and characterization. Furthermore, we show how the microrings can be integrated with other photonic devices on the silicon-on-insulator platform, and using proof-of-concept experiments, discuss the feasibility of using these photon-pair sources with technology that is already present in, or will soon be present in, practical fiber-optic networks, such as integrated lasers and modulated classical data streams.
Entangled photon sources are fundamental building blocks for quantum communication and quantum networks. Recently, silicon carbide emerged as a promising material for integrated quantum devices since it is CMOS compatible with favorable mechanical, electrical and photonic properties. In this work, we report the progress on the entangled photon pair generation at the telecom wavelength (1550 nm), which is achieved by implementing the spontaneous four-wave mixing process in a compact silicon carbide microring resonator. We will present the design principle, experimental set-up, and results of this work.
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.
Integrated quantum photonics leverages the on-chip generation of nonclassical states of light to realize key functionalities of quantum devices. Typically, the generation of such nonclassical states relies on whispering gallery mode resonators, such as integrated optical micro-rings, which enhance the efficiency of the underlying spontaneous nonlinear processes. While these kinds of resonators excel in maximizing either the temporal confinement or the spatial overlap between different resonant modes, they are usually associated with large mode volumes, imposing an intrinsic limitation on the efficiency and footprint of the device. Here, we engineer a source of time-energy entangled photon pairs based on a silicon photonic crystal cavity, implemented in a fully CMOS-compatible platform. In this device, resonantly enhanced spontaneous four-wave mixing converts pump photon pairs into signal/idler photon pairs under the energy-conserving condition in the telecommunication C-band. The design of the resonator is based on an effective bichromatic confinement potential, allowing it to achieve up to nine close-to-equally spaced modes in frequency, while preserving small mode volumes, and the whole chip, including grating couplers and access waveguides, is fabricated in a single run on a silicon-on-insulator platform. Besides demonstrating efficient photon pair generation, we also implement a Franson-type interference experiment, demonstrating entanglement between signal and idler photons with a Bell inequality violation exceeding five standard deviations. The high generation efficiency combined with the small device footprint in a CMOS-compatible integrated structure opens a pathway toward the implementation of compact quantum light sources in all-silicon photonic platforms.