Results 1 - 10 of 11544
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[en] Main architectures, principles and features of the high-speed serial data transceiver HDMP1022/1024 are described in the paper. Its work mode and its application circuit are also presented. In high-speed fiber-optic transmission system, the serial data transfer (up to 1 Gbps) is realized by this transceiver. (authors)
[en] Photonic crystal fibers present a wavelength-scale periodic microstructure running along their length. Their core and two-dimensional photonic crystal might be based on varied geometries and materials, enabling light guidance due to different propagation mechanisms in an extremely large wavelength range, extending to the terahertz regions. As a result, these fibers have revolutionized the optical fiber technology by means of creating new degrees of freedom in the fiber design, fabrication and applicability. This report aims to provide a detailed statement on the recent progress and novel potential applications of photonic crystal fibers.
[en] We experimentally and numerically investigate a diagnostic method for detecting hidden delamination in composite panels, using highly nonlinear solitary waves. Solitary waves are a type of nonlinear waves with strong energy intensity and non-distortive nature, which can be controllably generated in one-dimensional granular crystals. In this study, we use granular crystals as a combined sensor and actuator to detect hidden delamination in carbon fiber reinforced polymer (CFRP) composite panels. Specifically, we locally excite a CFRP composite specimen using the granular crystal as an actuator and measure the reflected waves that carry the specimen’s diagnostic information using the same device as a sensor. We first investigate the effect of the panel’s boundary conditions on the response of the reflected solitary waves. We then investigate the interactions of a solitary wave with delamination hidden in the CFRP composite specimen. Lastly, we define a damage index based on the solitary waves’ responses to identify the location of the hidden delamination in the CFRP composite panel. The solitary wave-based diagnostic method can provide unique merits, such as portable and fast sensing of composites’ hidden damage, thereby with the potential of being used for hot spot monitoring of composite-based structures. (paper)
[en] This book is one of series of information communication, which deals with measurement of communication. It is divided into six chapters. The contents are foundation of measurement with classification and principle, Basic measurement on current, voltage, electric resistance, power and impedance, measurement of communication line with way by L3 tester, BW tester and pulse tester, measurement of optical fiber cable of equipment and method, Test and measurement of information communication equipment about test of modulator and use, measurement of cable broadcasting equipment on transmission level and main transmission equipment.
[en] Due to its ability in providing long distance, distributed sensing, the optical fiber sensing technique based on a Brillouin optical time domain reflectometer (BOTDR) has a unique advantage in monitoring the stability and safety of linear structures. This paper describes the application of a BOTDR-based technique to measure the stress within precast piles. The principle behind the BOTDR and the embedding technique for the sensing optical fiber in precast piles is first introduced, and then the analysis method and deformation and stress calculation based on distributed strain data are given. Finally, a methodology for using a BOTDR-based monitoring workflow for in situ monitoring of precast piles, combined with a practical example, is introduced. The methodology requires implantation of optical fibers prior to pile placement. Field experimental results show that the optical fiber implantation method with slotting, embedding, pasting and jointing is feasible, and have accurately measured the axial force, side friction, end-bearing resistance and bearing feature of the precast pile according to the strain measuring data. (paper)
[en] This patent describes an apparatus including a radiation source which emits in a multiplicity of directions for focusing radiation on an object which may receive radiation within a certain solid angle. It comprises a first reflector and a second reflector, the first reflector being elliptical in cross section and having a first focus and a second focus, the second reflector being circular in cross section and having a center, and a radius equal to the distance between the second reflector and the first focus, the first reflector and the second reflector being arranged so that a concave reflecting surface of the first reflector faces a concave reflecting surface of the second reflector, and so arranged that the first focus of the first reflector corresponds to the center of the second reflector, the radiation source being an elongated discharge bulb, the object being a group of two or more optical fibers defining at least one line of optical fibers which are located at the second focus of the first reflector
[en] The characteristics and possible applications of scalpels based on diode and fibre lasers emitting at 0.97, 1.06, 1.56, and 1.9 μm, which are produced and developed by the IRE-Polyus Co., are presented. The advantages of such devices and the possibilities for increasing their output power and extending their spectral range are shown. (laser biology and medicine)
[en] In this work, the relation between 2D- and 3D-strain based piezoresistive gauge factors for carbon fiber filament in plane stress states is developed theoretically. For measuring the gauge factors, carbon fiber filaments are attached to the base specimen surface at different angles. Their resistance response to multidimensional strain field is investigated by four-point bending tests. Piezoresistive models of carbon fiber filament in plane stress states are created using the test results. In the test setup, carbon fiber filaments are placed both on the tension side and the compression side. Both the models show that the piezoresistive response of carbon fiber filament is dominated by the longitudinal strain. Based on the inequality in the sensitivities to tensile strain and compressive strain, the piezoresistive models are modified further. The modified piezoresistive models reveal the following 3D-strain based gauge factors: 1.82 for longitudinal tensile strain, 1.64 for longitudinal compressive strain, 0.10 for transverse tensile strain, and −0.25 for transverse compressive strain. The 2D-strain based gauge factors depend not only on the polarity of the longitudinal strain and transverse strain, but also on the polarity of the strain in the thickness direction. The piezoresistive models are verified experimentally. (paper)
[en] A theoretical method to obtain the propagation and coupling characteristics of channel optical waveguides is presented. The waveguides show graded-index profiles in both transverse directions. Commonly, they are fabricated by metal diffusion on LiNbO3. The method models the waveguide, in the vertical direction, by means a multilayer structure. We combine the effective index method with the WKB method to solve the whole waveguide. Propagation constants for isolated waveguides and results of coupling parameters for directional couplers are presented. (Author) 12 refs
[en] One of the most important requirements for optical fibres as waveguiding media is uniformity. Polarisation-maintaining anisotropic fibres contain a special type of nonuniformity, which leads to polarisation cross-talk: optical power is transferred from one polarisation mode to the orthogonal mode. In this paper, we report a technique for detecting and locating such nonuniformities in a PANDA anisotropic single-mode fibre using polarised reflectometry. (fiber optics)