Electro-optic routing of photons from single quantum dots in photonic integrated circuits

Recent breakthroughs in solid-state photonic quantum technologies enable generating and detecting single photons with near-unity efficiency as required for a range of photonic quantum technologies. The lack of methods to simultaneously generate and control photons within the same chip, however, has formed a main obstacle to achieving efficient multi-qubit gates and to harness the advantages of chip-scale quantum photonics. Here we propose and demonstrate an integrated voltage-controlled phase shifter based on the electro-optic effect in suspended photonic waveguides with embedded quantum emitters. The phase control allows building a compact Mach-Zehnder interferometer with two orthogonal arms, taking advantage of the anisotropic electro-optic response in gallium arsenide. Photons emitted by single self-assembled quantum dots can be actively routed into the two outputs of the interferometer. These results, together with the observed sub-microsecond response time, constitute a significant step towards chip-scale single-photon-source de-multiplexing, fiber-loop boson sampling, and linear optical quantum computing.Comment: 7 pages, 4 figues + supplementary informatio

Nanomechanical single-photon routing

The merger between integrated photonics and quantum optics promises new opportunities within photonic quantum technology with the very significant progress on excellent photon-emitter interfaces and advanced optical circuits. A key missing functionality is rapid circuitry reconfigurability that ultimately does not introduce loss or emitter decoherence, and operating at a speed matching the photon generation and quantum memory storage time of the on-chip quantum emitter. This ambitious goal requires entirely new active quantum-photonic devices by extending the traditional approaches to reconfigurability. Here, by merging nano-optomechanics and deterministic photon-emitter interfaces we demonstrate on-chip single-photon routing with low loss, small device footprint, and an intrinsic time response approaching the spin coherence time of solid-state quantum emitters. The device is an essential building block for constructing advanced quantum photonic architectures on-chip, towards, e.g., coherent multi-photon sources, deterministic photon-photon quantum gates, quantum repeater nodes, or scalable quantum networks.Comment: 7 pages, 3 figures, supplementary informatio

Curved GaAs cantilever waveguides for the vertical coupling to photonic integrated circuits

We report the nanofabrication and characterization of optical spot-size converters couplers based on curved GaAs cantilever waveguides. Using the stress mismatch between the GaAs substrate and deposited Cr-Ni-Au strips, single-mode waveguides can be bent out-of-plane in a controllable manner. A stable and vertical orientation of the out-coupler is achieved by locking the spot-size converter at a fixed 90$^\circ$ angle via short-range forces. The optical transmission is characterized as a function of temperature and polarization, resulting in a broad-band chip-to-fiber coupling extending over a 200 nm wavelength bandwidth. The methods reported here are fully compatible with quantum photonic integrated circuit technology with quantum dot emitters, and open opportunities to design novel photonic devices with enhanced functionality

Independent operation of two waveguide-integrated quantum emitters

We demonstrate the resonant excitation of two quantum dots in a photonic integrated circuit for on-chip single-photon generation in multiple spatial modes. The two quantum dots are electrically tuned to the same emission wavelength using a pair of isolated $p$-$i$-$n$ junctions and excited by a resonant pump laser via dual-mode waveguides. We demonstrate two-photon quantum interference visibility of $(79\pm2)\%$ under continuous-wave excitation of narrow-linewidth quantum dots. Our work solves an outstanding challenge in quantum photonics by realizing the key enabling functionality of how to scale-up deterministic single-photon sources.Comment: 7 pages 3 figures, Supplementary materials 7 pages 9 figure

Spin-photon interface and spin-controlled photon switching in a nanobeam waveguide

Access to the electron spin is at the heart of many protocols for integrated and distributed quantum-information processing [1-4]. For instance, interfacing the spin-state of an electron and a photon can be utilized to perform quantum gates between photons [2,5] or to entangle remote spin states [6-9]. Ultimately, a quantum network of entangled spins constitutes a new paradigm in quantum optics [1]. Towards this goal, an integrated spin-photon interface would be a major leap forward. Here we demonstrate an efficient and optically programmable interface between the spin of an electron in a quantum dot and photons in a nanophotonic waveguide. The spin can be deterministically prepared with a fidelity of 96\%. Subsequently the system is used to implement a "single-spin photonic switch", where the spin state of the electron directs the flow of photons through the waveguide. The spin-photon interface may enable on-chip photon-photon gates [2], single-photon transistors [10], and efficient photonic cluster state generation [11]

La création entre artistes, écrivains et lecteurs

La portée du numérique va bien au-delà du bouleversement de notre quotidien. En effet, il s\u27agit également d\u27un outil voire d\u27un mode de fonctionnement qui élargit considérablement les possibilités de la création, qu\u27elle soit artistique ou littéraire

La création entre artistes, écrivains et lecteurs

La portée du numérique va bien au-delà du bouleversement de notre quotidien. En effet, il s\u27agit également d\u27un outil voire d\u27un mode de fonctionnement qui élargit considérablement les possibilités de la création, qu\u27elle soit artistique ou littéraire

Infobesity and quality of life: Survey in French public transportation

International audienceNowadays, information is at the very heart of our everyday life, and more precisely in publictransportation. Indeed, it is often chosen to be the location of various dissemination of information such aspractical information, network news, advertising, weather forecast, newsflashes, kidnapping alerts, safetyrecommendations in a general post-attack environment…Being informed could be a necessity to insure citizens a certain quality of life, but there is also a risk ofbeing too informed. Does the large amount of information have an impact on our sense of well-being? In orderto question the effect of information, we performed a survey in Lyon’s tramways. Our study was conducted intwo different stages:1. Observation of information broadcasts within the public transportation, which enabled us to develop atypology of the kinds of information displayed.2. Interviews with public transportation users, based on a questionnaire that examines the attention givento broadcast information by users, especially in terms of emotions and sense of well-being.Our survey was conducted in one day, between 11:00 am and 2:00pm, on one of the tramway line thatdeserves several universities and the train station. We also asked the questions on the platform, which is thefavourite place for calls for vigilance. In terms of statistics, we questioned almost half men (51%) and halfwomen (49%). We also paid attention to the frequency with which people were using public transportation,considering that the impact of a big amount of information is important, when people are often confronted to it

On-Chip Nanomechanical Filtering of Quantum-Dot Single-Photon Sources

Semiconductor quantum dots in photonic integrated circuits enable scaling quantum-information processing to many single photons and quantum-optical gates. On-chip spectral filters are essential to achieve high-purity and coherent photon emission from quantum dots embedded in waveguides, without resorting to free-space optics. Such spectral filters should be tunable, to compensate for the inhomogeneous spectral distribution of the quantum dots transitions. Here, we report an on-chip filter monolithically integrated with quantum dots, that uses nanomechanical motion for tuning its resonant wavelength over 10 nm, enabling operation at cryogenic temperatures and avoiding cross-talk with the emitter. We demonstrate single-photon emission from a quantum dot under non-resonant excitation by employing only the on-chip filter. These results are key for the development of fully-integrated de-multiplexing, multi-path photon encoding schemes, and multi-emitter circuits