Use of Cross-Couplers to Decrease Size of UV Written Photonic Circuits

Kundys, Dmytro; Gates, James C.; Dasgupta, Sonali; Gawith, C.B.E.; Smith, Peter G. R.

doi:10.1109/lpt.2009.2021071

Cited by 25 publications

(23 citation statements)

References 11 publications

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“…The individual waveguides were written by focusing a continuous-wave UV laser (244 nm wavelength) onto the chip, which is subsequently moved transversely to the surface normal with computer-interfaced 2D motion control. The UV-writing process enables creation of beam splitters (X couplers) by crossing waveguides at different angles 38 . These are much smaller than traditional directional couplers, which helps to reduce the effect of propagation loss in more complex circuits.…”

Section: Methodsmentioning

confidence: 99%

Multiphoton quantum interference in a multiport integrated photonic device

et al. 2013

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Increasing the complexity of quantum photonic devices is essential for many optical information processing applications to reach a regime beyond what can be classically simulated, and integrated photonics has emerged as a leading platform for achieving this. Here we demonstrate three-photon quantum operation of an integrated device containing three coupled interferometers, eight spatial modes and many classical and nonclassical interferences. This represents a critical advance over previous complexities and the first on-chip nonclassical interference with more than two photonic inputs. We introduce a new scheme to verify quantum behaviour, using classically characterised device elements and hierarchies of photon correlation functions. We accurately predict the device's quantum behaviour and show operation inconsistent with both classical and bi-separable quantum models. Such methods for verifying multiphoton quantum behaviour are vital for achieving increased circuit complexity. Our experiment paves the way for the next generation of integrated photonic quantum simulation and computing devices.

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Section: Methodsmentioning

confidence: 99%

Multiphoton quantum interference in a multiport integrated photonic device

et al. 2013

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“…We use X-couplers [12] instead of the more typical directional couplers. These X-couplers can be thought of as the zeroth-order version of a directional couplerincoming light couples evanescently between the modes for less than one-quarter of a sine wave while transiting the device.…”

Section: X-couplersmentioning

confidence: 99%

Modular linear optical circuits

Mennea¹,

Clements²,

Smith³

et al. 2018

Optica

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We propose and demonstrate a modular architecture for reconfigurable on-chip linear-optical circuits. Each module contains 10 independent phase-controlled Mach-Zehnder interferometers; several such modules can be connected to each other to build large reconfigurable interferometers. With this architecture, large interferometers are easier to build and characterize than with traditional, bespoke, monolithic designs. We demonstrate our approach by fabricating three modules in the form of UV-written silica-on-silicon chips. We characterize these chips, connect them to each other, and implement a wide range of linear optical transformations. We envisage that this architecture will enable many future experiments in quantum optics.

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“…Waveguides of typical 4.5µm×4.5µm dimension were formed as a result of UV-induced permanent refractive index change inside the photosensitive waveguide core layer. The UV-writing process enables creation of complex networks utilising compact X couplers [30], the splitting ratio of which can be selected by adjusting the waveguide crossing angle during the UV-writing process. Compact X-couplers have a number of advantages over more traditional directional couplers i.e.…”

Section: Device Fabricationmentioning

confidence: 99%

Quantum teleportation on a photonic chip

et al. 2014

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Quantum teleportation is a fundamental concept in quantum physics [1] which now finds important applications at the heart of quantum technology including quantum relays [2,3], quantum repeaters [4] and linear optics quantum computing (LOQC) [5,6]. Photonic implementations have largely focussed on achieving long distance teleportation due to its suitability for decoherence-free communication [7][8][9]. Teleportation also plays a vital role in the scalability of photonic quantum computing [5,6], for which large linear optical networks will likely require an integrated architecture. Here we report the first demonstration of quantum teleportation in which all key parts-entanglement preparation, Bellstate analysis and quantum state tomographyare performed on a reconfigurable integrated photonic chip. We also show that a novel elementwise characterisation method is critical to mitigate component errors, a key technique which will become increasingly important as integrated circuits reach higher complexities necessary for quantum enhanced operation.Quantum teleportation is essential to many schemes for universal fault-tolerant quantum computation, making it an important protocol for any physical implementation of a quantum information processor [10,11]. In their seminal work, Knill, Laflamme, and Milburn showed that such a quantum processor could be constructed using only linear optical elements, at the expense of rendering each quantum logic gate probabilistic [5]. Adapting the teleportation scheme of Gottesman and Chuang [6], they then showed that this protocol could be efficiently scaled to a large number of concatenated gates, motivating a renewed interest in building more complex linear optical circuits for quantum information processing [11]. Realizing such a scheme requires building large, sophisticated networks of nested optical interferometers. This motivates the use of waveguides integrated onto compact and inherently stable photonic chips, and pioneering work has shown the viability of this approach for two- [12][13][14] and three-photon interference experiments [15][16][17]. These latter works highlighted the problems caused by photon loss, low data rates, and fabrication imperfections which make the extension to even higher photon numbers far from straightforward.Whilst photonic experiments were the first to realize quantum teleportation [18,19], demonstrations of this protocol in a waveguide architecture have been limited to fiber-based experiments [9,20]. Although there has been recent progress [21], no integrated photonic experiments have yet been able to demonstrate actual teleportation, due to the difficulty in realizing three photonic qubits on a sufficiently complex circuit [15]. In particular, integrated components require careful attention to fabricated deviations from design and the effects of increased and potentially unbalanced propagation loss. Experimental verification that integrated photonic circuits continue to perform well as their complexity increases is therefore of considerable interes...

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Use of Cross-Couplers to Decrease Size of UV Written Photonic Circuits

Cited by 25 publications

References 11 publications

Multiphoton quantum interference in a multiport integrated photonic device

Multiphoton quantum interference in a multiport integrated photonic device

Modular linear optical circuits

Quantum teleportation on a photonic chip

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