Laser diode beam divergence is the main parameter for beam shaping and fiber optic coupling. Increasing the waveguide layer thickness is the conventional method to decrease the beam divergence. In this paper, the broadened asymmetric waveguide is introduced to decrease the divergence without increasing the optical power. The asymmetric waveguide was used to shift the vertical optical field to n...

A numerical study of second-harmonic (SH) generation in a corrugated polymer waveguide is performed with a rigorous electromagnetic theory. Comparison with experiment reveals the role of losses inside the waveguide-small losses do not significantly affect the nonresonant response and reduce the resonant enhancement of SH generation. High losses can lead to the opposite effect-instead of enhance...

Prism coupling and reflection spectroscopy are used to characterize bound modes within composite right/left handed terahertz metamaterial waveguides. The cavity antenna model is used to understand the polarization dependence of the radiative coupling to TM00 and TM01 waveguide modes. Furthermore, the cavity model along with transmission-line theory is used to derive a surface impedance model fo...

A comprehensive theory is developed for describing the nonlinear propagation of optical pulses through silicon waveguides with nanoscale dimensions. Our theory includes not only the vectorial nature of optical modes but also the coupling between the transverse electric and magnetic modes occurring for arbitrarily polarized optical fields. We have studied the dependence of relevant nonlinear par...

We use coupled mode theory, adequately incorporating optical losses, to model ultra-broadband terahertz (THz) waveguide emitters (0.1-20 THz) based on difference frequency generation of femtosecond infrared (IR) optical pulses. We apply the model to a generic, symmetric, five-layer, metal/cladding/core waveguide structure using transfer matrix theory. We provide a design strategy for an efficie...

ABSTRACT One dimensional digital waveguides are widely used to model travelling pressure waves along wind instrument bores. These models must also account for frequency-dependent losses occurring along the bore walls, and at boundaries. This is accomplished by incorporating waveguide filter elements, which are based on the widely accepted theory describing these losses. A measurement technique ...

The interaction of multiple waveguide modes with a relativistic electron beam in an overmoded, single-frequency, cyclotron autoresonance maser amplifier is analyzed using a nonlinear self-consistent model and kinetic theory. It is shown analytically, and confirmed by simulation, that all of the coupled waveguide modes grow at the spatial growth rate of the dominant unstable mode, but suffer dif...

We present the design and experimental results of an optically controlled high power pulse compression system. The rf parameters of the system are chosen to fit the requirements of the X-band Next Linear Collider design at SLAC. The system is based on the switched resonant delay line theory [1]. The high power microwave switch, required for this system, is realized using optical excitation of a...

We propose a nanoplasmonic waveguide side-coupled with bright-dark-dark resonators in our paper. A multi-oscillator theory derived from the typical two-oscillator model, is established to describe spectral features as well as slow-light effects in bright-dark-dark structures, and confirmed by the finite-difference time domain (FDTD). That a typical plasmon induced transparency (PIT) turns to do...

This paper presents the Waveguide Filter Design (WFD) program using principle of electromagnetic wave theory and Wave Iterative Method (WIM) based on propagation of incident, reflected and transmitted waves in the waveguide for microwave engineering education. After the surveying by questionnaire about the nature in the microwave engineering course, the instructors found that the microwave engi...