A novel compact dual-band bandpass waveguide filter is presented in this paper. H-plane metal inserts with complementary split-ring resonators are implemented as resonating elements in the standard (WR-90) rectangular waveguide. Design starts from the models of the waveguide resonators with two resonant frequencies (9 GHz and 11 GHz) using a single flat or folded metal insert. Further, folded i...

Ah.WoCl-A m u l t i o d e fih+matched arrayed waveguide grating-based demultiplexer has befn demonstrated. In thb design. multimode waveguides have been used 85 m y clements. The device, which can he used in short-dbtance communications, has been realized using low-cos1 polymer planar waveguide technology. Three wavclenglh ehanncls were SUCC~S. fully separsled. The average fiber-to-fiber inserl...

This paper presents a review of the development of long-period waveguide gratings (LPWGs) with focus on the realization of various kinds of tunable devices, such as band-rejection filters, variable attenuators, band-pass filters, and add/drop multiplexers. A number of specific examples are given to demonstrate how the geometry and material flexibility of the optical waveguide technology facilit...

Substrate integrated waveguide (SIW) is a new form of transmission line. It facilitates the realization of nonplanar (waveguide based) circuits into planar form for easy integration with other planar (microstrip) circuits and systems. This paper describes the design of an SIW to microstrip transition. The transition is broadband covering the frequency range of 8 – 12GHz. The measured in-band in...

We introduce a low refractive index layer between the metal and the gain medium in metal-coated laser resonators and demonstrate that it can significantly reduce the dissipation losses. Analysis of a gain medium waveguide shows that for a given waveguide radius, the low index layer has an optimal thickness for which the lasing threshold gain is minimal. The waveguide analysis is used for the de...

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...

This paper presents a novel concept of half wavelength doubleridged half height rectangular waveguide resonator. The basic design consists of a double-ridged rectangular waveguide placed between two rectangular waveguide WR2300. The resonance frequency, bandwidth, Q factor etc. can be controlled by varying the ridge parameters such as ridge length, width, height, ridge gap width, ridge gap heig...

Terahertz (THz) digital holography is employed to investigate the properties of waveguides. By using a THz digital holographic imaging system, the propagation modes of a metallic coaxial waveguide are measured and the mode patterns are restored with the inverse Fresnel diffraction algorithm. The experimental results show that the THz propagation mode inside the waveguide is a combination of fou...

We propose a novel ultra-low loss single-mode hollow-core waveguide using subwavelength high-contrast grating (HCG). We analyzed and simulated the propagation loss of the waveguide and show it can be as low as 0.006 dB/m, three orders of magnitude lower than the lowest loss of the state-of-art chip-scale hollow waveguides. This novel HCG hollow-core waveguide design will serve as a basic buildi...