Search results

The purpose of this paper is to present a complete analysis of leaky modes within a microstructured optical fibre (MOF). Some new numerical results illustrating the versatility and accuracy of our approach are to be given.

A method involving both finite elements and perfectly matched layer (PML) is proposed.

A rigorous definition of the leaky modes is proposed that leads to a proof of the validity of the PML approach together with a rule for the choice of the PML parameters.

The choice of parameters associated with the PML are discussed in great detail. The accuracy of the constant of propagation (and especially the imaginary part) are highlighted.

This paper aims to review various techniques used in computational electromagnetism such as the treatment of open problems, helicoidal geometries and the design of arbitrarily shaped invisibility cloaks. This seemingly heterogeneous list is unified by the concept of geometrical transformation that leads to equivalent materials. The practical set‐up is conveniently effected via the finite element method.

The change of coordinates is completely encapsulated in the material properties.

The most significant examples are the simple 2D treatment of helicoidal geometries and the design of arbitrarily shaped invisibility cloaks.

The paper provides a unifying point of view, bridging several techniques in electromagnetism.

This paper investigates new technological devices to be utilised in future optical communications, by means of variational method (FEM) and multipole scattering approach (Rayleigh method). This last one provides interesting asymptotic results in the long‐wavelength limit. The so‐called photonic crystal fibres (PCF) possess radically different guiding properties due to photonic band gap guidance: removing a hole within a macro‐cell leads to a defect state within the gap. In the case of multi‐core PCF, the localised modes start talking to each other which possibly leads to a new generation of multiplexer/demultiplexers.

In this paper, we study a new class of optical fibers to be utilized in future optics and optoelectronics. These so‐called photonic band gap (PBG) waveguides can be classified into a fundamentally different way to all optical waveguides and possess radically different guiding properties due to PBG guidance, as opposed to guidance by total internal reflection.

This paper is devoted to the presentation of a new finite element formulation for spectral problems arising in the determination of propagating modes in dielectric waveguides and particularly in optical fibers. As an example, we compute the coupling between two parallel optical wave guides. The originality of the paper lies in the fact that we take into account both the vector character of the problem (no weak coupling assumption) and the unboundness of the domain.

This paper concerns the study of non‐linear effects in optical fibres with a core made of a Kerr type medium. The aim is to propose an algorithm to find spatial solitons, i.e. solutions with a harmonic behaviour in time and along the fibre but with a field distribution in the cross‐section corresponding to a self‐trapped propagation of the electromagnetic field.

The field is supposed to be harmonic in time and along the direction of invariance of the fibre but inhomogeneous in the cross‐section. This modifies the refractive index profile of the fibre (a step‐index one in this study). A scalar model of the fibre, together with the finite element method (that is well suited to deal with inhomogeneous media), is used and a new iterative algorithm is proposed to obtain the non‐linear solutions. An adaptive meshing is necessary to guarantee the accuracy of the model.

The new algorithm converges to self‐coherent solutions that are different from those obtained via a fixed power algorithm. The equivalents both of a fundamental mode and of a second order mode are studied.

The approach acknowledges the findings of the previously known spatial solitons (with a slight modification of the algorithm) together with a new family of solutions. It opens a new field of investigation to understand this whole family of non‐linear solutions as it shows that only a small part of them was known up to now.

The purpose of this paper is to present a geometric approach to the problem of dimensional reduction. To derive (3 + 1) D formulations of 4D field problems in the relativistic theory of electromagnetism, as well as 2D formulations of 3D field problems with continuous symmetries.

The framework of differential‐form calculus on manifolds is used. The formalism can thus be applied in arbitrary dimension, and with Minkowskian or Euclidean metrics alike.

The splitting of operators leads to dimensionally reduced versions of Maxwell's equations and constitutive laws. In the metric‐incompatible case, the decomposition of the Hodge operator yields additional terms that can be treated like a magnetization and polarization of empty space. With this concept, the authors are able to solve Schiff's paradox without use of coordinates.

The present formalism can be used to generate concise formulations of complex field problems. The differential‐form formulation can be readily translated into the language of discrete fields and operators, and is thus amenable to numerical field calculation.

The approach is an evolution of recent work, striving for a generalization of different approaches, and deliberately avoiding a mix of paradigms.

This paper aims to model a three-dimensional twisted geometry of a twisted pair studied in an electrostatic approximation using only two-dimensional (2D) finite elements.

The proposed method is based on the reformulation of the weak formulation of the electrostatics problem to deal with twisted geometries only in 2D.

The method is based on a change of coordinates and enables a faster computational time as well as a high accuracy.

The effectiveness of the adopted approach is demonstrated by studying different configurations related to the IEC 60851-5 standard defined for the measurement of the electrical properties of the insulation of the winding wires used in electrical machines.

This paper aims to focus on research work related to metamaterial-based sensors for material characterization that have been developed for past ten years. A decade of research on metamaterial for sensing application has led to the advancement of compact and improved sensors.

In this study, relevant research papers on metamaterial sensors for material characterization published in reputed journals during the period 2007-2018 were reviewed, particularly focusing on shape, size and nature of materials characterized. Each sensor with its design and performance parameters have been summarized and discussed here.

As metamaterial structures are excited by electromagnetic wave interaction, sensing application throughout electromagnetic spectrum is possible. Recent advancement in fabrication techniques and improvement in metamaterial structures have led to the development of compact, label free and reversible sensors with high sensitivity.

The paper provides useful information on the development of metamaterial sensors for material characterization.

Proposes to posit a clear definition of the energy stored in general electromagnetic media.

A general setting of thermodynamics using differential geometry is used and it is shown how the Poynting identity fits in.

A general method of defining the energy storage and dissipation in a general media is stated.

It appears that the definition of the energy stored in a dispersive media is not a state variable and depends on the history of the field variation.

If an electromagnetic model has to be coupled to a mechanical or thermal one, the associated forces and/or heat dissipations may not be clearly defined if one merely knows the electromagnetic constitutive relations.

It proposes a very general setting for the thermodynamic of electrodynamic media.