Structure of modes of smoothly irregular three-dimensional integrated optical four-layer waveguide

An asymptotic method is used for researching an integrated optical multilayer waveguide satisfying the condition of the smooth modification of the shape of the studied three-dimensional structure. Three-dimensional fields of smoothly deforming modes of the integrated optical waveguide are described analytically. An evident dependence of the contributions that the first order of smallness makes to the amplitudes of the electrical and magnetic fields of the quasi-waveguide modes is obtained. The canonical type of equations describing the propagation of quasi-TE and quasi-TM modes in the smoothly irregular part of a four-layer integrated optical waveguide is represented for an asymptotic method. With the help of the method of coupled waves and the perturbation theory method, the shifts of complex propagation constants for quasi-TE and quasi-TM modes are obtained in an explicit form. The elaborated theory is applicable for an analysis of similar structures of dielectric materials, magnetic materials, and metamaterials over a wide enough range of electromagnetic wavelengths.     

Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell’s equations is made to obey “inclined” boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of “entanglement” of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lüneburg lens.     

Asymptotics of eigenwaves of a smooth irregular spherical anisotropic waveguide

Based on the Debye series modified with respect to the method of horizontal beams and vertical modes, the asymptotics of eigenwaves of a smooth irregular anisotropic spherical anisotropic waveguide channel is constructed.State University, St. Petersburg. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 5, pp. 457–466, May, 1995.     

Silicon-on-insulator irregular waveguide mode converters

Irregular waveguide elements in a silicon-on-insulator platform that allow new device concepts are introduced. Specific designs are achieved using a multiresolution optimization strategy where the waveguide width is varied in stepwise increments. Simulation results are given for high-efficiency waveguide mode converters, power splitters, and waveguide transitions operating at 1.55 microm. The degrees of freedom available permit these functions and small dimensions, making these devices candidates for optical integrated circuits.     

Separable equations for a cylindrical anisotropic elastic waveguide

A separable form of the equations of motion for a cylindrical anisotropic elastic waveguide of arbitrary cross-section is derived. From these the orthogonality relation for the modes of harmonic wave propagation in the waveguide is readily derived.     

New waveguide modes in anisotropic structures

The existence of new hybrid waveguide modes of properly tailored integrated optical waveguides consisting of ultrathin films clad by positive birefringent media is pointed out.     

Demonstration of mode conversion in an irregular waveguide

Communications wavelength waveguide mode conversion is demonstrated in an irregular metal-walled structure that was designed by using multiresolution optimization. Strong scatter and a large number of degrees of freedom allowed high-efficiency conversion in a device having a length of just a few wavelengths. The fabrication approach draws on standard semiconductor processing. Mode-selective reflectors, splitters, phase shifters, and other elements can be achieved by using this principle.