Biomedical subjects

Shyqyri Haxha

Publications and source records attributed to Shyqyri Haxha.

4 recordsLinked to original sources

PubMed2006

Optimization of compact lateral, vertical, and combined tapered spot-size converters by use of the beam-propagation method.

A study of lateral, vertical, and combined spot-size converters is presented that employs full-vectorial numerical techniques such as modal solution and beam propagation based on the finite-element method. Spot-size expansion, coupling efficiency to an optical fiber, the mode-beating phenomenon, and transmission losses are demonstrated for all three spot-size-converter designs. Optimization of the device fabrication parameters is also reported. A significant improvement in the coupling efficiency and reduction of the device length are achieved when the length and the width are changed simultaneously.

Journal Article↗

PubMed2005

Numerical modeling of polarization conversion in semiconductor electro-optic modulators.

An accurate numerical simulation study of a polarization conversion phenomenon in deeply etched semiconductor electro-optic waveguide modulators is presented. Based on a powerful and versatile finite element package, the effect of various imperfect fabrication conditions on unwanted and unexpected polarization conversion in electro-optic semiconductor modulators is, for the first time to our knowledge reported and explained in terms of its origin.

Journal Article↗

PubMed2003

Velocity matching of a GaAs electro-optic modulator.

New designs for the velocity matching of a deep-etched semiconductor electro-optic modulator are presented. A tantalum pentoxide (Ta2O5) coating is considered here for achieving velocity matching between the microwave and the optical signals. The effects of the velocity mismatch, the conductor loss, the dielectric loss, and the impedance mismatch are studied in relation to the optical bandwidth of a high-speed semiconductor modulator. It is shown that both the dielectric loss and the impedance matching play key roles for velocity-matched high-speed modulators with low conductor loss. The effects of Ta2O5 thickness on the overall bandwidth and on the half-wave voltage-length product VpiL are also reported.

Journal Article↗

PubMed2003

Bandwidth estimation for ultra-high-speed lithium niobate modulators.

The effects of velocity matching, impedance matching, conductor loss, and dielectric loss on the optical bandwidth of an ultra-high-speed lithium niobate modulator are reported. It is shown that both dielectric loss and impedance matching play a key role for velocity-matched high-speed modulators with low conductor loss. The effects of etch depth, buffer thickness, electrode width, and thegap between the electrodes on device performance are also illustrated.

Journal Article↗