We compare different inverse scattering (IS) algorithms used to calculate profiles of fibre Bragg gratings (FBGs) and analyse their robustness, speed and implementation difficulties. We analyse sources of IS algorithm errors and discuss their relative importance. We discuss the optimal choice of IS algorithm for inverse-direct iterative optimisation schemes for grating design.
View Article and Find Full Text PDFWe analyze the interactions of (2+1) -dimensional parametric solitons and demonstrate nonplanar beam switching in a bulk X((2)) medium, which includes controllable soliton repulsion, spiraling, and fusion. An analytical model predicting the results of the soliton scattering is derived and verified by direct numerics.
View Article and Find Full Text PDFWe demonstrate that weak parametric interaction of a fundamental beam with its harmonic field in a Kerr medium can drastically modify the beam dynamics, giving rise to very complex bifurcation phenomena and quasi solitons. Most importantly, we reveal a novel physical mechanism of the collapse suppression in a bulk optical Kerr medium: parametric coupling to a weakly radiating harmonic field.
View Article and Find Full Text PDFA core component of all scanning near-field optical microscopy (SNOM) systems is the optical probe, which has evolved greatly but still represents the limiting component for the system. Here, we introduce a new type of optical probe, based on a Fractal Fibre which is a special class of photonic crystal fibre (PCF), to directly address the issue of increasing the optical throughput in SNOM probes. Optical measurements through the Fractal Fibre probes have shown superior power levels to that of conventional SNOM probes.
View Article and Find Full Text PDFThere were adduced the results of studying of cellular and humoral factors of the immunity in a brief-lasting ischemia-reoxygenation of the extremities in 56 patients with surgical diseases and in 31 pupils, in whom the organism reactivity lowering was revealed. It was established, that changes in the ischemia-reoxygenation of the extremities are multifactorial and they are connected primarily with the immunocompetent cells activation. Nonmedicinal method of the "tourniquet" immunocorrection was proposed, which is recommended as a concurrent one - for the recovery acceleration or solely - in the treatment of inflammatory diseases.
View Article and Find Full Text PDFPhys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics
September 2000
We demonstrate that weak parametric interaction of a fundamental beam with its third harmonic field in Kerr media gives rise to a rich variety of families of nonfundamental (multihumped) solitary waves. Making a comprehensive comparison between bifurcation phenomena for these families in bulk media and planar waveguides, we discover two types of soliton bifurcations and other interesting findings. The latter includes (i) multihumped solitary waves without even or odd symmetry and (ii) multihumped solitary waves with large separation between their humps which, however, may not be viewed as bound states of several distinct one-humped solitons.
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