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Sprengers, J. P., Gaggero, A., Sahin, D., Jahanmirinejad, S., Frucci, G., Mattioli, F., et al. (2011). Waveguide superconducting single-photon detectors for integrated quantum photonic circuits. Appl. Phys. Lett., 99(18), 181110(1–3).
Abstract: The monolithic integration of single-photon sources, passive optical circuits, and single-photon detectors enables complex and scalable quantum photonic integrated circuits, for application in linear-optics quantum computing and quantum communications. Here, we demonstrate a key component of such a circuit, a waveguide single-photon detector. Our detectors, based on superconducting nanowires on GaAs ridge waveguides, provide high efficiency (~0%) at telecom wavelengths, high timing accuracy (~0 ps), and response time in the ns range and are fully compatible with the integration of single-photon sources, passive networks, and modulators.
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Lee, B. G., Assefa, S., Green, W. M. J., Min Yang, Schow, C. L., Jahnes, C. V., et al. (2011). Multichannel high-bandwidth coupling of ultradense silicon photonic waveguide array to standard-pitch fiber array. J. Lightwave Technol., 29(4), 475–482.
Abstract: A multichannel tapered coupler interfacing standard 250-μm-pitch low-numerical-aperture (NA) polarization-maintaining fiber arrays with ultradense 20- μm-pitch high-NA silicon waveguides is designed and fabricated. The coupler is based on an array of 12 dual-core glass waveguides on 250-μ m pitch that are tapered to a 20- μm pitch, simultaneously providing both pitch and spot-size conversion. At the wide end, the inner core matches the NA and mode profile of standard single-mode fiber. When drawn and tapered, the inner core “vanishes†and the outer core, surrounded by the clad, matches the NA and mode profile of the on-chip photonic waveguide. Ultradense high-efficiency coupling to an array of Si photonic waveguides is demonstrated using a 12-channel polarization-maintaining-fiber pigtailed tapered coupler. Coupling to Si waveguides is facilitated using SiON spot-size converters integrated into the Si photonic IC to provide 2-3-μm mode field diameters compatible with the tapered coupler. The tapered coupler achieves <; 1 dB coupling losses to photonic waveguides. Furthermore, eight-channel coupling is shown with less than -35 dB crosstalk between channels. Finally, a 640-Gb/s wavelength-division-multiplexing signal is coupled into four waveguides occupying 80 μm of chip edge, providing 160-Gb/s per-channel bandwidths.
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(2011). ГОСТ 3.1102-2011. ЕСТД. Стадии разработки и виды документов. Общие положения.
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Galeazzi, M. (2011). Fundamental noise processes in TES devices. IEEE Trans. Appl. Supercond., 21(3), 267–271.
Abstract: Microcalorimeters and bolometers are noise-limited devices, therefore, a proper understanding of all noise sources is essential to predict and interpret their performance. In this paper, I review the fundamental noise processes contributing to Transition Edge Sensor (TES) microcalorimeters and bolometers and their effect on device performance. In particular, I will start with a simple, monolithic device model, moving to a more complex one involving discrete components, to finally move to today's more realistic, comprehensive model. In addition to the basic noise contribution (equilibrium Johnson noise and phonon noise), TES are significantly affected by extra noise, which is commonly referred to as excess noise. Different fundamental processes have been proposed and investigated to explain the origin of this excess noise, in particular near equilibrium non-linear Johnson noise, flux-flow noise, and internal thermal fluctuation noise. Experimental evidence shows that all three processes are real and contribute, at different levels, to the TES noise, although different processes become important at different regimes. It is therefore time to discard the term “excess noise” and consider these terms part of the “fundamental noise processes” instead.
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Belitsky, V., Desmaris, V., Dochev, D., Meledin, D., & Pavolotsky, A. (2011). Towards Multi-Pixel Heterodyne Terahertz Receivers. In Proc. 22th Int. Symp. Space Terahertz Technol..
Abstract: Terahertz multi-pixel heterodyne receivers introduce multiple challenges for their implementation, mostly due to the extremely small dimensions of all components and even smaller tolerances in terms of alignment, linear dimensions and waveguide component surface quality. In this manuscript, we present a concept of terahertz multi-pixel heterodyne receiver employing optical layout using polarization split between the LO and RF. The frontend isbased on a waveguide balanced HEB mixer for the frequency band 1.6 – 2.0 THz. The balanced HEB mixer followsthe layout of earlier demonstrated APEX T2 mixer. However for the mixer presented here, we implemented split-block layout offering inimized lengths of all waveguides and thus reducing the associated RF loss. The micromachining methods employed for producing the mixer housing and the HEB mixer chip are very suitable for producing multiple structures and hence are in-line with requirements of multi-pixel receiver technology. The demonstrated relatively simple mounting of the mixer chip with self-aligning should greatly facilitate the integration of such multi-channel receiver. Index Terms—Instrumentation, Multi-pixel, Terahertz, Waveguide Balanced Mixer.
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