Integrated optic devices - such as optical fibers, waveguides or linear optical circuits - offer distinct advantages for quantum information applications. The experimental setups get miniaturized, the spatial properties of generated quantum states are defined by the guiding geometries and networks are intrinsically stable. We present a toolbox for integrated quantum devices.
Integrated optic devices - such as optical fibers, waveguides or linear optical circuits - offer distinct advantages for quantum information applications. The experimental setups get miniaturized, the spatial properties of generated quantum states are defined by the guiding geometries and networks are intrinsically stable. We present a toolbox for integrated quantum devices.
Although practical realisation of a fully functioning quantum computer is still a long way off, recent progress both experimentally and theoretically is paving the way for possible implementations. One of the leading approaches is quantum optics, where photons are used as carriers of quantum information, and are manipulated in both linear and non-linear optical circuits. More recently, advances in integrated quantum photonics are enabling the realisation of compact and stable quantum gates and circuits. This approach provides routes to enhancing the complexity of quantum optic experiments, and ultimately towards the development of advanced quantum technologies. This study presents an overview of recent developments in the field of integrated waveguide quantum circuits. Key building blocks required for the realisation of quantum circuits are presented, and a rudimentary version of Shor's quantum factoring algorithm is demonstrated. Planar waveguide quantum circuits provide a high-performance platform from which quantum technologies and experimental quantum physics using single photons can be developed, and a new generation of quantum information and computing devices can be monolithically integrated onto a single optical chip.
Optical fibers are the backbone of the world's communication systems. They also represent the simplest example of a photonic device, where photons in waveguides replace electrons in wires. More sophisticated devices than this can be made, in which all the optical components – including multiple waveguided modes – are integrated on a chip. It is important to understand the quantum noise properties of these systems. While in some respects these systems can be treated as one-dimensional, there are additional features. Dispersion is due not just to material properties, but also to the waveguide geometry. The nonlinearity comes from a combination of material and geometric properties as well. There is, of course, a quantum aspect to these photonic devices, in which quantum noise occurs due to random effects caused by nonlinearity and gain. Optical devices based on waveguides are, of course, not just simple fibers. One can have multiple waveguides with various types of linear coupling. The intrinsic nonlinearity of the dielectric leads to four-wave mixing, which can be an important source of correlated photons, both for fundamental tests of quantum mechanics, and for applications in quantum information. It is often essential to include effects due to anisotropies of various types, as well as material dispersion. In dielectrics, another effect that should be included is the coupling of vibrational modes of the (solid) dielectric to the propagating field, which gives rise to Raman and Brillouin scattering effects. This allows us to obtain a more detailed and correct theory of quantum noise than the simplified case treated in Chapter 3.
Quantum Optics Devices on a Chip provides a comprehensive understanding of how the integration of advanced quantum technologies and photonics is revolutionizing multiple industries, making it essential for anyone interested in the future of quantum innovation. Quantum Optics Devices on a Chip is situated at the intersection of several disciplines and industries, driving advancements in quantum technology and integrated photonics. The development of quantum optics devices on a chip represents a significant breakthrough. Chip-scale integration involves designing and fabricating optical devices, such as waveguides, modulators, detectors, and light sources, on a micro- or nanoscale chip. This miniaturization enables the integration of multiple components on a single chip, leading to compact, efficient, and scalable quantum optical systems. Quantum sensing applications, such as magnetometry, gyroscopy, and biosensing, can benefit from miniaturized, high-performance devices integrated on a chip, allowing for the seamless integration of quantum optical functionalities with existing photonic circuits. This integration holds promise for applications in telecommunications, data communication, and optical signal processing. Overall, the development of quantum optics devices on a chip represents a significant step forward in the advancement of quantum technology. It brings together principles from physics, materials science, engineering, and computer science to enable the practical implementation of quantum phenomena for a wide range of applications across industries. Quantum Optics Devices on a Chip serves as a comprehensive guide to this rapidly evolving field, providing insights and knowledge, exploring the contributions it has made to the disciplinary and industrial development of quantum optics devices on a chip.
Recent achievements in the area of integrated quantum optics and quantum information processing have shown impressive progress for the implementation of linear circuits based on monolithic waveguide structures. Most experiments are based on χ(3) -media, such as glas, silicon-on insulator or silica-on-silicon. In these platforms the implementation of highly efficient sources, frequency converters and fast active phase shifters and modulators pose severe challenges. The use of advanced waveguides structures, which harness a χ(2) –non-linearity, allows for the realization various devices with multiple functionalities. These include single- and multi-channel sources with high brightness, quantum frequency conversion with tailored spectral-temporal properties, and circuits comprising degenerate pair generation in orthogonal polarization, linear elements, and active elements such as polarization rotators or an electro-optically controllable time delay. Here we present our latest progress for the implementation of integrated devices based on χ(2) –media for quantum circuits and quantum communication systems.
Integrated optical waveguide circuits are becoming increasingly important in quantum information processing. They provide a platform that is scaleable to multiple qubits, offers stability over the timescales required for multiple photon coincidence based measurements, and by utilizing telecommunications sources and hardware, allows low-loss and efficient operation. This work will present recent results and indicate research directions that are leading towards the demonstration of the required range of functions on chip, particularly on chip, sources, system tomography, phase control operations and detection.
Recent progress in the field of quantum information processing has highlighted the prospects of using integrated optical devices for quantum applications. Integrated quantum photonics offers several advantages compared to free-space setups. Not only the miniaturization, which dramatically reduces the size of the building blocks and allows imprinting or cascading several functions on a single substrate, but also the possibility to reproduce the same photonic circuit many times on the same chip. For instance, this has been exploited to spatially multiplex heralded single-photon, leading to an increase of the single-photon emission rate at constant noise level. More strikingly, one can think of combining, on-chip, several synchronised single photon sources towards engineering large photon-number entangled states. Despite this attractive potential, only few examples of spatial mul- tiplexing have been reported in the literature due to the technological challenge related to fabrication processes. On one hand, lithium nio- bate (LN) is very suitable for quantum integrated photonics since it shows both optic-optic and electro-optic non-linearities, as well as the possibility to integrate low-loss waveguides. However, several parallel and/or cascaded optical functions require various lithographic steps leading to reduced yields. On the other hand, femto-second laser direct-writing (FLDW) technique on glass-type substrates, allows fast fabrication of low-loss waveguide circuits requiring no lithographic masks nor chemical exchange. However, no efficient non-linear processes are available in SiO2 waveguides for photon-pair generation. We discuss here an integrated photonic chip able to generate photon-number states which consists of three photonic chips fabricated on either LN for photon generation or on SiO2 substrates for photon manipulation purposes. Our approach takes advantage of the best features of both worlds.