High-Q semi-2D-photonic crystal cavities with a tapered edge and side-coupled bus waveguide are demonstrated. With a quadratic design, the unloaded cavity presents a theoretical ultrahigh quality factor up to 6.7 × 10(7) for the condition that there are mere 34 holes in the propagated direction, which is pretty close to the 2D and 1D counterpart. Combined with a side-coupled bus waveguide, an a...

The Integrated Optics has resulted in miniaturization of optical devices. Bent waveguides have replaced straight waveguides in optical integrated circuits for such reasons. In the proposed work, curved/bent waveguide is basic structure for generating delay and hence the phase shift. A differential phase shift is obtained by the differential length change between the straight waveguide and a S-b...

An easy-to-fabricate but very efficient fiber-to-waveguide coupler is theoretically analyzed and experimentally demonstrated. In this design, light from a single-mode fiber can be butt-coupled into a single-mode high-index-contrast Si3N4/SiO2 waveguide with a measured coupling efficiency of 96 % at the wavelength of 1550 nm, and > 90 % in the spectral range from 1450 nm to 1650 nm. Large horizo...

BACKGROUND We describe the design, the construction and performance of a narrow band ortho-mode transducer, currently used in the 5 GHz polarimetric receiver of the Galactic Emission Mapping project. RESULTS The ortho-mode transducer was designed to achieve a high degree of transmission within the 400 MHz of the GEM band around the 5 GHz (4.8-5.2 GHz). It is composed of a circular-to-square w...

Conventional CPV systems focus sunlight directly onto a PV cell, usually through a non-imaging optic to avoid hot spots. In practice, many systems use a shared tracking platform to mount multiple smaller aperture lenses, each concentrating light into an associated PV cell. Scaling this approach to the limit would result in a thin sheet-like geometry. This would be ideal in terms of minimizing t...

We present a novel design of a waveguide to microstrip or coplanar waveguide transition using a unilateral finline taper. The transition from the unilateral finline mode to the TEM microstrip mode is done directly, avoiding the antipodal finline tapers that have commonly been employed. This results in significant simplification of the design and fabrication, and shortening of the chip length, t...

In this paper, a model for the analysis and design of a reflective Arrayed Waveguide Grating is presented. The device consists of one half of a regular AWG where each arm waveguide in the array is terminated with a phase shifter and a Sagnac loop reflector. By individually adjusting the phase shifter and Sagnac reflectivity in each arm, additional functionality to that previously reported in th...

We investigate the device physics of novel GaAs waveguide photodetectors with integrated photon multiplication. Such detectors have the potential to achieve simultaneously high saturation power, high speed, high responsivity, and quantum efficiencies above 100%. Our device design vertically combines a bulk photodetector ridge waveguide region with laterally confined quantum wells for amplificat...

The paper presents the design of a novel ultra-wideband microwave crossover for the use in microstrip circuits. The proposed structure includes a double microstrip-coplanar waveguide (CPW) vertical interconnect in single-layer substrate technology which allows an inclusion of a finite-width coplanar waveguide (CPW) on the top side of the substrate to achieve the required cross-link. The present...

question I am frequently asked is, “Why do the antenna dimensions in the W1GHZ Microwave Antenna Book — Online not include the probe dimensions (for the transition from waveguide to coaxial transmission line)?” The answer is that the transition is part of the transmission line, not the antenna, and does not directly affect the performance of an antenna. The transition may be right at the antenn...