We study intermodal four-wave mixing (FWM) in few-mode fibers in the presence of birefringence fluctuations and random linear mode coupling. Two different intermodal FWM processes are investigated by including all nonlinear contributions to the phase-matching condition and FWM bandwidth. We find that one of the FWM processes has a much larger bandwidth than the other. We include random linear m...

in this research, using the modified compression field theory (mcft), a new truss based model is proposed to predict the behavior of reinforced concrete coupling beams with diagonal reinforcement. the model is able to consider the effects of shear and axial forces and bending moment, simultaneously. the proposed model includes a nonlinear shear spring, an axial spring, two inclined truss member...

a complete linear theory in four dimensional space-time is constructed for propagation and coupling of electromagnetic waves in the most general case, i.e. media where all three space directions are in homogeneous and where temporal changes, anisotropy and absorbtion are also included. the only condition is that the properties of the medium should be slowly varying, although it is assumed that ...

We present a coupled-mode theory of fiber-optic add-drop filters, which involve directional coupling between two fibers combined with fiber Bragg gratings defined inside the coupling region. The analysis self-consistently accounts for both the directional and the reflection coupling, and the propagation constants and structure of the supermodes of the combined structure are derived. We present ...

We analyze the coupling between the fundamental vector modal fields of two parallel polarization-maintaining fibers. An improved coupled-mode theory is employed, which also applies to anisotropic materials. Results for the array-mode-propagation constants are presented as a function of the relative tilt angle between the principal axes of the two fibers.

The formalism of coupled-mode theory is adopted for describing nonlinear pulse propagation in optical fibers, the coupling being induced by the nonlinear part of the refractive index. This approach describes in a natural way the influence of the waveguide, and in principle allows of the possibility of investigating soliton propagation when more than one mode is excited.

A discussion of linear dynamics and nonlinear evolution of modes belonging to the shear Alfvhn branch is presented. Attention is focused to the modes which exist near the gap of the continuous spectrum. A discussion of the relative importance of mode-mode coupling, E x B trapping and stochastic losses is also presented.

Marco Bernabei, ∗ Angel J. Moreno, and Juan Colmenero 2, 3 Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain. Centro de F́ısica de Materiales (CSIC, UPV/EHU)-Materials Physics Center, Apartado 1072, 20080 San Sebastián, Spain. Departamento de F́ısica de Materiales, Universidad del Páıs Vasco (UPV/EHU), Apdo. 1072, 20080 San Sebastián, Spain. (Dated: J...