We present an adiabatic taper design in three dimensions for coupling light into photonic crystal defect waveguides in a square lattice of circular dielectric rods. The taper is a two-stage structure in which the first stage makes the transition from a dielectric waveguide to a coupled-cavity waveguide. The second stage subsequently transforms the waveguide mode from an index-guided mode to a b...

A typical confocal resonator for THz radiation produced by an FEL will have a waist that is larger than the gap of the undulator. Hence waveguiding is required. Here we consider a resonator consisting of two spherical mirrors and a cylindrical waveguide in between. The radii of curvature for the mirrors are chosen to image the ends of the waveguide onto themselves. We discuss the properties of ...

A typical confocal resonator for THz radiation produced by an FEL will have a waist that is larger than the gap of the undulator. Hence waveguiding is required. Here we consider a resonator consisting of two spherical mirrors and a cylindrical waveguide in between. The radii of curvature for the mirrors are chosen to image the ends of the waveguide onto themselves. We discuss the properties of ...

We present an experimental demonstration of a new class of hybrid gap plasmon waveguides on the silicon-on-insulator (SOI) platform. Created by the hybridization of the plasmonic mode of a gap in a thin metal sheet and the transverse-electric (TE) photonic mode of an SOI slab, this waveguide is designed for efficient adiabatic nanofocusing simply by varying the gap width. For gap widths greater...

We propose a novel subwavelength terahertz (THz) waveguide based on the magnetic plasmon polariton mode guided by a narrow gap in a negative permeability metamaterial. Deep subwavelength waveguiding (<lambda/10) with group velocities down to c/21.8 is demonstrated in a straight waveguide, a 90 degrees bend, and a splitter. The proposed waveguiding system inherently has no cutoff for any core wi...

In This paper, optical Filter based on photonic crystal ring resonator with square lattice is proposed. The add-drop filter is designed by coupling in line quasi waveguide and resonant cavity. Photonic band gap is obtained by plane wave expansion method (PWE) and Simulation is carried out by Finite Difference Time Domain method (FDTD).This type of add-drop filter provide high transmission effic...

We developed a new building block for constructing planar microwave circuitry: bulk titanium waveguide. The waveguide is formed by deep trench etching, dielectric gap filling, and planarization. The high aspect ratio of the resulting structure provides superior field confinement, low crosstalk, therefore a small footprint. To enable bulk titanium as a substrate compatible with microfabrication,...

We show that the properties of the confined modes of a photonic band-gap ~PBG! waveguide can be calculated with good accuracy by replacing it with an effective corrugated waveguide that represents only the structure in the vicinity of the middle slab. Such a replacement is helpful in the design of the PBG waveguides as well as in the understanding and analysis of the coupling of different waveg...