We study light-beam propagation in a nonlinear coupler with an asymmetric double-channel waveguide and derive various analytical forms of optical modes. The results show that the symmetry-preserving modes in a symmetric double-channel waveguide are deformed due to the asymmetry of the two-channel waveguide, yet such a coupler supports the symmetry-breaking modes. The dispersion relations reveal...

In this paper a new procedure for designing forward-wave directional couplers using periodic shunt short circuited stubs is proposed. A new type of cell using these stubs, which enlarge the phase difference between even- and odd modes of a uniform microstrip coupled line is introduced. Using the equivalent circuit model for even- and odd-modes of the proposed cell, the elements of the  ABCD tra...

A miniature, multifunctional hybrid organic directional coupler (HDC), constructed from two different flexible crystals, splits the optical signal and delivers input-dependent outputs.

In order to overcome the main drawbacks of coaxial, waveguide, and stripline couplers, the analysis and the design of a compact coaxial-to-microstrip directional coupler convenient for power and antenna control application, are presented using the method of moments (MoM) in two dimensions. This technique is adapted to study the complex configuration of the line’s system, which does not have a s...

We study two-component surface solitons in a pair of linearly coupled truncated waveguiding arrays with the Kerr nonlinearity. Symmetric solitons have a very small stability area, while those that are antisymmetric and asymmetric are stable in vast regions. Below a critical value of the coupling constant, branches of the symmetric and asymmetric modes separate, and accordingly, asymmetric solit...

The nonlinear fiber coupler is considered as a Hamiltonian dynamical system with an infinite number of degrees of freedom, with the soliton states of the coupler being the singular points of this dynamical system. Numerical simulations show that arbitrary initial conditions give rise, asymptotically, to oscillations around some of the stable singular points and some amount of radiation. Example...

We present a detailed study of the generation photon pairs by spontaneous four-wave mixing in structure composed two linearly uncoupled resonators, where energy can be transferred from one resonator to another only through nonlinear interaction. Specifically, we consider case racetrack-shaped resonators connected coupler designed guarantee that resonance comb each tuned independently and allow ...

Existence of a surface wave along the boundary between the semi-infinite materials, one of which is a free-space and the other is a material with either negative permeability or negative permittivity, is theoretically investigated. Surface waves exist in only limited combination of negative and positive signs of the material parameters. In addition, by analyzing the surface wave in a finite-thi...