Perpendicular Waveguides Research Articles

Theoretical studies of dual optical and acoustic unidirectional filtering based on two-dimensional phoxonic crystals with rectangle defects

ABSTRACT Dual optical and acoustic unidirectional transmission in two-dimensional phoxonic crystal rectangular defect connected by two mutually perpendicular waveguides is theoretically achieved. The unidirectional filtering for both optical and acoustic waves is designed by altering the phoxonic crystal waveguides and cavity to obtain the modes’ match and mismatch via the finite element method. This kind of devices has the abilities of mode convertor, wavelength filtering and unidirectional propagation for both the optical and acoustic wave, and maybe potentially applied in simultaneously manipulating light and sound.

Simultaneous unidirectional reciprocal filters of electromagnetic and elastic waves based on the modal symmetry of phoxonic crystal waveguides and cavity

We theoretically achieve the simultaneous unidirectional reciprocal filter of electromagnetic (EM) and elastic waves in a single phoxonic crystal by the finite-element method. The functionality is achieved by matching and mismatching the modal symmetry between a resonant cavity and two mutually perpendicular waveguides. Suitable phoxonic cavity and waveguides are created to realize the match and mismatch of the modal symmetry for both EM and elastic waves. The proposed device has the abilities of phoxonic unidirectional filtering as well as providing great potential for enhancing acousto-optic coupling by simultaneously tailoring electromagnetic and elastic waves with an ultracompact footprint size.

Low-cross-talk and high-contrast all optical bistable switching based on coupled defects in a nonlinear photonic crystal cross-waveguide geometry

We present a photonic crystal all-optical bistable switch configuration consisting of crossing perpendicular waveguides geometry with instantaneous Kerr nonlinearity. A microcavity is added to the signal waveguide which is coupled with the defect at the waveguide intersection to increase the transmission contrast. We demonstrate with the finite-difference time-domain method that such a configuration can function as a low crosstalk and high contrast all-optical switch.

A Continuous Fluidized Bed Microwave Paddy Drying System Using Applicators with Perpendicular Slots on a Concentric Cylindrical Cavity

This article presents a continuous fluidized bed microwave drying system that provided a higher drying capacity than that provided by comparable conventional hot air drying systems. Its applicator consists of perpendicular slots over a concentric cylindrical cavity that is excited by perpendicular waveguides. The paddy to be dried was dropped vertically into the center of the applicator while hot air at 60°C, heated by magnetron ventilation, was injected from the opposite direction. Statistical data on the temperature distribution of the paddy, which scattered over the whole volume of the applicator, were collected and analyzed together with the probability of its orientation, position, and density. A suitable system was proposed, constructed, and tested. It provided good quality dried paddy, similar to that from a fluidized bed drying system. The system's maximum leakage power of 4.8 mW/cm2 was well within the safety standard. With only 5.2 kJ of energy consumption, this system reduced the moisture content of a large quantity of paddy from 24 to 14% (wb) with a capacity of 3.1 kg/h. The energy cost for drying was US$47.7/ton.

Transmission through metallic array slits curved with perpendicular waveguides

The transmission of normally incident plane wave through an array of subwavelength metallic slits curved with perpendicular waveguides has been explored. Two-dimensional electromagnetic fields inside and near the metal film are simulated by the finite-difference time-domain (FDTD) method. The perpendicular waveguides in the middle of slits affect the modes of slits in two different manners: commonly, the extended length of the waveguides leads to the increase of the resonant wavelength; shifting the waveguides location along the vertical slits, red or blue shift of resonant wavelengths can be achieved, however to some confirmed length of the perpendicular waveguides, there is the only one resonant wavelength. In addition, a new explanation model is proposed in which the resonance is ascribed to three reasons: the Fabry–Perot cavity theory, the surface current flow, and the surface charges. All the calculated results are well explained by our proposed model.

An applicator for uniform heating using perpendicular slots on a concentric cylindrical cavity excited by perpendicular waveguides

This paper presents an applicator that provides uniform heating by using perpendicular slots on a concentric cylindrical cavity excited by perpendicular waveguides. A concentric cylindrical cavity is designed to operate in both the TM z and TE z modes simultaneously. These modes are excited by perpendicular waveguides. The slot array of each mode is cut along the circumference of the inner surface of the applicator. Appropriate cavity dimension, slot length and position, improve the temperature distribution. The combination of two applicators aligned in an overlapped fashion realizes uniform temperature distribution in the material to be heated. This applicator is suitable for continuous microwave heating systems in agricultural product dryer.

Low-loss submicrometer silicon-on-insulator rib waveguides and corner mirrors.

Rib microwaveguides are demonstrated on silicon-on-insulator substrates with Si film thickness of either 380 or 200 nm and a width of 1 microm. Corner mirrors that allow compact 90 degrees turns between two perpendicular waveguides are characterized. Measured propagation losses are approximately 0.4 dB/cm and approximately 0.5 dB/cm for 380-nm and 200-nm Si film, respectively, and mirror losses are approximately 1 dB. This allows the development of applications such as optical interconnects in integrated circuits over propagation distances larger than several centimeters.

Elimination of cross talk in waveguide intersections

We present general criteria for crossing perpendicular waveguides with nearly 100% throughput and 0% cross talk. Our design applies even when the waveguide width is of the order of the wavelength. The theoretical basis for this phenomenon is explained in terms of symmetry considerations and resonant tunneling and is then illustrated with numerical simulations for both a two-dimensional photonic crystal and a conventional high-index-contrast waveguide crossing. Cross-talk reduction by up to 8 orders of magnitude is achieved relative to unmodified crossings.

Cross coupled cavity semiconductor laser

A novel monolithic coupling scheme in which three or four active waveguides interact interferometrically to form a multicavity semiconductor laser is demonstrated. The coupling between perpendicular waveguides is obtained by an integrated beamsplitter. Frequency selection, tunability, and single mode operation are demonstrated.