Low Loss Orientation-Patterned Gallium Arsenide (OPGaAs) Waveguides for Nonlinear Infrared Frequency Conversion

The mid-IR frequency band (λ = 2-5 µm) contains several atmospheric transmission windows making it a region of interest for a variety of medical, scientific, commercial, and military applications. Recently there has been a growing interest in using orientation-patterned semiconductors such as orientation-patterned gallium arsenide (OPGaAs) to achieve frequency conversion in this region. GaAs has a large nonlinear coefficient, broad transparency range, and a well-developed fabrication technology allowing for the manufacture of nonlinear integrated optical devices such as waveguides. By confining the nonlinear pump beam throughout the length of a waveguide one can achieve very high field intensities while at the same time overcoming the diffraction normally associated with tight focusing of Gaussian beams. However, device performance in OPGaAs waveguides has been limited by large propagation losses resulting from the unique nature of the material. In this dissertation I report an OPGaAs/OPAlxGa1-xAs embedded ridge waveguide design which, combined with a new growth process using alternating MOCVD growth and chemical mechanical polishing (CMP), is capable of achieving the low losses necessary to function effectively as a nonlinear gain material. Our waveguide was designed to be single mode from 2-10 µm, based upon a series of numerical simulations to determine the effective indices of the waveguide across the mid-IR band, which was crucial for accurate calculation of the grating period Λ needed for quasi-phasematching. Record low RMS surface roughness values of 5 nm were obtained using this new growth process. In addition, record low waveguide losses of 1.0 dB/cm were measured, validating our theoretical predictions, and nonlinear gain was investigated in an optical parametric amplifier (OPA) experiment.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical Engineering

Grantor dc:publisher

University of Dayton

Year dc:date

2012

Author dc:creator

• Kemp, Izaak V.

Contributors dc:contributor

• Sarangan, Dr. Andrew

• Electrical Engineering
• waveguides
• nonlinear optics
• lasers
• infrared

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=dayton1355429124

OAI identifier oai:identifier

oai:etd.ohiolink.edu:dayton1355429124