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A novel wide‐angle finite‐difference beam‐propagation method is applied to the analysis of confinement losses in photonic crystal fibers (PCFs). The method is formulated in terms of the locally one‐dimensional (LOD) technique and Padé polynomials. It was found that the wide‐angle approach allows an acceleration of the convergence rate of up to 50% for the effective‐index imaginary part when compared to paraxial formalism. In this framework, an important aspect of PCF structures, namely, the random structural variation of the hole radius and pitch, which occurs during the fabrication process of these devices, is investigated in this paper. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 568–573, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20882

Abstract-We assess the performance of three unconditionally stable finite-difference time-domain (FDTD) methods for the modeling of doubly dispersive metamaterials: 1) locally one-dimensional FDTD; 2) locally one-dimensional FDTD with Strang splitting; and (3) alternating direction implicit FDTD. We use both double-negative media and zero-index media as benchmarks.

SUMMARYThis paper presents a comparative study among three different formulations to analyse optical waveguides. All treatments, namely, full-vectorial, semi-vectorial, and scalar are based on the successive over relaxation-SOR technique. A complete expansion of these three formulations together with a convergence study of the respective iterative relaxation parameters are also provided. Several waveguiding structures are investigated in this work, including D-shaped fibres, rib waveguides, and photonic crystal fibres, addressing the accuracy of the several FD-SOR formulations implemented. It is demonstrated that the semi-vectorial approach produces excellent results when compared to those obtained with the full-vectorial treatment.

The design and performance of microstructured optical fibers (MOFs) for simultaneous dispersion compensation and Raman amplification is numerically investigated. We studied a lumped Raman amplifier designed to compensate the signal loss and dispersion introduced by a 100-km, 16-channel C-band WDM link. The impairments induced by the nonlinearities caused by the small mode area of the designed MOF are investigated and the analysis is extended to include non-ideal factors such as excess background losses, splice loss, and the geometry variations 255 256 S. P. N. Cani et al.during the fabrication process. The results are discussed and compared to those obtained for conventional dispersion compensating fibers (DCFs).

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In this work, a modified patch antenna with broad bandwidth and small size is proposed and investigated. Instead of rectangular patch of a known antenna we use a rounded patch. This modification increases significantly the upper frequency edge of the operating band. This allows one to obtain a -10 dB return loss bandwidth of 72 % and to flatten the gain characteristic. In our study, we use the parametric optimization of geometry of the antenna.Index Terms-Patch antenna, T-shaped probe feeding, shorted wall, broadband.

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