Title of dissertation: MODELING AND DESIGN OF MICROWAVE-MILLIMETERWAVE FILTERS AND MULTIPLEXERS Yunchi Zhang, Doctor of Philosophy, 2006 Dissertation directed by: Professor Kawthar A. Zaki Department of Electrical and Computer Engineering Modern communication systems require extraordinarily stringent speci…cations on microwave and millimeter-wave components. In mobile and integrated communicati...

A numerically efficient model for the evaluation of InGaAsP ridge waveguide laser operation at threshold is presented. It includes the treatment of the electrical behaviour of the junction and an 'hybrid' optical waveguide analysis that approximately takes into account the coupling between TE and TM modes at the ridge interfaces. The adopted optical model is slightly more complex than the effec...

Conventional metallic waveguides have several major advantages, including low propagation losses and high power transmissions in the microwave frequency range. One disadvantage of metallic waveguides is that the propagation frequency band is limited at frequencies above the cutoff frequency fc. The usable frequency range is therefore restricted to fc < f < 2fc, because the TE20 mode can exist i...

We demonstrate a single frequency, 1.55 m wavelength laser based on an asymmetric twin-waveguide structure using a single growth step and a simple fabrication process. The external Bragg grating is formed on the passive ridge waveguide, optically coupled to the twin-guide gain section using a low loss, tapered mode transformer. The grating is produced by near-field holographic printing using a ...

We report the reduced waveguiding efficiency for the signals around 1560 nm as the injection current of an GaAs/ AlGaAs multiple quantum well laser diode (lasing wavelength at 840 nm) with a ridge-loading waveguide configuration increased. This reduction trend stopped when the injection current reached the threshold condition of the laser diode. The decreased waveguide transmission and the more...

We studied the influence of focused ion beam milling ridge waveguides on lasing parameters edge-emitting lasers, based a separate confinement double heterostructure. It is shown that there are three degrees influence, according to etching depth: modification waveguide properties only, decrease in efficiency without changing threshold current, and simultaneous deterioration current with signific...

We report a new type of plasmonic nanoscale ridge aperture and its fabrication process which is based on layer-by-layer planar lithography. This new fabrication method allows us to create desired nanoscale features of a plasmonic ridge waveguide nanoscale aperture, which helps to confine a near-field spot to sub-wavelength dimensions. Numerical simulations using Finite Element Method (FEM) are ...