Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
On-chip quantum teleportation
B. J. Metcalf, Nicholas L. Thomas-Peter, Justin B. Spring, P. C. Humphreys, Nathan K. Langford, W. Steven Kolthammer, Marco Barbieri, Xian‐Min Jin, Brian J. Smith, Ian A. Walmsley, James C. Gates, Dmytro O. Kundys, Peter G. R. Smith
Integrated quantum optics provides great promise for enabling photonic experiments to reach new regimes of complexity. Chip-based fabrication enables sophisticated networks involving multiple interfering pathways in a compact and stable physical architecture. In a recent work we demonstrated an advance in the complexity of these integrated devices by showing the first quantum interference of three separate input photons. Such complexity allows the demonstration of three qubit protocols never before realised on-chip. Here, we report the first results showing quantum teleportation on an integrated photonic circuit. Quantum teleportation provides the mechanism for quantum relay schemes and is an important constituent in linear optical quantum computing. Whilst demonstrations to date have relied upon complex and fragile bulk optical systems, being able to teleport quantum states on a compact and stable integrated architecture will be a critical step towards scalable realisations of these schemes.
Integrated quantum optics provides great promise for enabling photonic experiments to reach new regimes of complexity. Chip-based fabrication enables sophisticated networks involving multiple interfering pathways in a compact and stable physical architecture. In a recent work we demonstrated an advance in the complexity of these integrated devices by showing the first quantum interference of three separate input photons. Such complexity allows the demonstration of three qubit protocols never before realised on-chip. Here, we report the first results showing quantum teleportation on an integrated photonic circuit. Quantum teleportation provides the mechanism for quantum relay schemes and is an important constituent in linear optical quantum computing. Whilst demonstrations to date have relied upon complex and fragile bulk optical systems, being able to teleport quantum states on a compact and stable integrated architecture will be a critical step towards scalable realisations of these schemes.
Quantum teleportation is a crucial function in quantum networks. The implementation of photonic quantum teleportation could be highly simplified by quantum photonic circuits. To extend chip-to-chip teleportation distance, more effort is needed on both chip design and system implementation. In this work, we demonstrate a time-bin-based chip-to-chip photonic quantum teleportation over optical fibers under the scenario of a star-topology quantum network. Three quantum photonic circuits are designed and fabricated on a single chip, each serving specific functions: heralded single-photon generation at the user node, entangled photon pair generation and BSM at the relay node, and projective measurement of the teleported photons at the central node. The unbalanced Mach-Zehnder interferometers (UMZI) for time-bin encoding in these quantum photonic circuits are optimized to reduce insertion losses and suppress noise photons generated on the chip. Besides, an active feedback system is employed to suppress the impact of fiber length fluctuation between the circuits, achieving a stable quantum interference for the BSM in the relay node. As a result, a photonic quantum teleportation over optical fibers of 12.3 km is achieved based on these quantum photonic circuits, showing the potential of chip integration for the development of quantum networks.
Quantum computing shows great potential in solving highly complex computational challenges in multiple applications, including artificial intelligence, chemical modelling, biology simulation, portfolio optimization, drug delivery, logistical planning, etc. Quantum networking can enable secure communication as well as scalable interconnects of multiple quantum processing units. We need to scale up the number of high-quality qubits and make quantum systems more compact, robust, and lower cost to further improve the performance of quantum computing and networking. Photonic integrated circuits (PICs) can play a significant role in reducing the size, improving the stability, and reducing the system bring-up time of optical subsystems. QuEra’s recent progress shows the potential of leveraging PICs as a viable solution to facilitate the builds of highly scalable and high-performance quantum computers [1]. These results position integrated photonics as a critical enabling technology for next-generation large-scale quantum systems and invite broader participation from the photonics community in advancing quantum technologies with significant industrial impact.
Quantum information science aims to harness uniquely quantum mechanical properties to enhance measurement and information technologies, and to explore fundamental aspects of quantum physics. Of the various approaches to quantum computing [1], photons are particularly appealing for their low-noise properties and ease of manipulation at the single qubit level [2]. Encoding quantum information in photons is also an appealing approach to quantum communication, metrology (eg. [3]), measurement (eg. [4]) and other quantum technologies [5]. However, the implementation of optical quantum circuits with bulk optics has reached practical limits. We have developed an integrated waveguide approach to photonic quantum circuits for high performance, miniaturisation and scalability [6]. Here we report high-fidelity silica-on-silicon integrated optical realisations of key quantum photonic circuits, including two-photon quantum interference and a controlled-NOT logic gate [7]. We have demonstrated controlled manipulation of up to four photons on-chip, including high-fidelity single qubit operations, using a lithographically patterned resistive phase shifter [8]. We have used this architecture to implement a small-scale compiled version of Shorʼs quantum factoring algorithm [9] and demonstrated heralded generation of tuneable four photon entangled states from a six photon input [10]. We have combined waveguide photonic circuits with superconducting single photon detectors [11]. We describe complex quantum interference behaviour in multi-mode interference devices with up to eight inputs and outputs [12], and quantum walks of correlated particles in arrays of coupled waveguides [13]. Finally, we give an overview of our recent work on fundamental aspects of quantum measurement [14,15] and single photon sources [16,17].
Integrated photonic quantum chips have emerged as a promising platform for realizing fault-tolerant photonic quantum computers. Compared with bulk-optics systems, integrated photonics offer compact device footprints, enhanced programmability, and exceptional stability, attributes that are essential for executing large-scale and computationally demanding quantum tasks. In this review, we provide a comprehensive overview of recent advances in both discrete-variable and continuous-variable universal photonic quantum computation. We survey progress in fault-tolerant architectures and state-of-the-art integrated platforms and highlight the key challenges that must be addressed to scale photonic systems toward full fault tolerance. Finally, we outline future opportunities and research directions aimed at bridging the gap between current proof-of-principle demonstrations and fully scalable quantum microprocessors.
Quantum entanglement and teleportation are the key resources building the backbone of quantum technologies, such quantum communications, quantum networks, and quantum computations. The quantum communication networks are based on long-range distribution of entangled photons and teleportation of photon qubit states. The resource efficient measurement-based quantum computing models relies on cluster entangled states and the teleportation of logical operations between qubit sites. Silicon photonics provides a versatile platform for quantum information processing on chip, thanks to the CMOS-compatible fabrication process, ability to integrate thousands of components, and precise manipulation of quantum states on a single chip. Here we show our recent work on quantum entanglement and quantum teleportation technology based our advanced silicon photonics platform, a significant step towards future quantum network and optical quantum computing.
We investigate an integrated optical circuit on lithium niobate designed to implement a teleportation-based quantum relay scheme for one-way quantum communication at a telecom wavelength. Such an advanced quantum circuit merges for the first time both optical–optical and electro-optical nonlinear functions necessary for implementing the desired on-chip single-qubit teleportation. On the one hand, spontaneous parametric down-conversion is used to produce entangled photon pairs. On the other, we take advantage of two photon routers, consisting of electro-optically controllable couplers, to separate the paired photons and to carry out a Bell state measurement, respectively. After having validated all the individual functions in the classical regime, we performed a Hong–Ou–Mandel experiment to mimic a one-way quantum communication link. Such a quantum effect, seen as a prerequisite towards achieving teleportation, has been obtained at one of the routers when the chip was coupled to an external single-photon source. The two-photon interference pattern shows a net visibility of 80%, which validates the proof of principle of a 'quantum relay circuit' for qubits carried by telecom photons. In the case of optimized losses, such a chip could increase the maximal achievable distance of one-way quantum key distribution links by a factor of 1.8. Our approach and results emphasize the potential of integrated optics on lithium niobate as a key technology for future reconfigurable quantum information manipulation.