Surface waves can propagate on the planar interface of a linear electro-optic (EO) material and an isotropic dielectric material, for restricted ranges of the orientation angles of the EO material and the refractive index of the isotropic material. These ranges can be controlled by the application of a dc electric field, and depend on both the magnitude and the direction of the dc field. Thus, surface-wave propagation can be electrically controlled by exploiting the Pockels effect.

Bridging the so-called "last mile" in communication networks has revived keen interest in free-Space Optics (FSO), also known as fiber-free or fiberless optics, which is a technology that transports data via laser technology. It is a line-of-sight technology that currently enables optical transmission up to 2.5 Gbps of data, voice and video through the air at long distances (4km), allowing optical connectivity without deploying fiber-optic cable or securing spectrum licenses. It is moving closer to being a realistic alternative to laying fiber in access networks. This paper presents an introduction to FSO and the current state of its technology.

An evolutionary programming algorithm with a mixed continuous‐discrete parameter representation for application in electromagnetic optimization problems is presented. In our approach, the mutation operator consists of a hybrid combination of Gaussian mutation for the continuous parameters, and Poisson mutation for the discrete parameters. The implementation uses self‐adaptive schemes for updating the standard deviation of the Gaussian distribution and the mean of the Poisson distribution during the evolution. As an example, the proposed evolutionary algorithm is applied to the constraint designs of various multilayer dielectric‐filter structures. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 267–271, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11187

The dispersion equation for surface waves--with simple transverse exponential decay at the interface of identical biaxial crystals with a relative twist about the axis normal to the interface and propagating along a bisector of the angle between the crystallographic configurations on either side of the interface--has several solutions of which only one is physical. The selected type of surface wave is possible only for a restricted range of the twist angle, which depends on the ratio of the maximum and the minimum of the principal refractive indexes and the angle between the optic ray axes.

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