Nonlinear Optics in Waveguides Coupled With Photonic Band Gap Structures

University Of Dayton, Dayton OH

Investigators

Abstract

0140109 Haus The PI proposes to design, fabricate, characterize, and test waveguide-geometry, periodically textured nonlinear optical devices. Proton exchange and reverse proton exchange processes will be used to fabricate waveguides in lithium niobate. The superstrate is patterned over a wide area using UV laser lithography. The PI has developed the capability to fabricate one- (1D) and two-dimensional (2D) photonic band gap (PBG) structures with the UV laser facility with lattice constants varied from 150 nm to about 2 microns. Patterning will be done using plasma etching techniques, especially inductively coupled plasma etching to control reactivity and retain anisotropy of the etch process. The optical properties of the waveguides, such as mode index and loss, will be characterized in our laboratories. The laser diode pumps will be used to make compact, short wavelength, emission sources. Other spin-off applications will be examined, such as, terahertz wave generation, PBG-based electro-optic modulators, and parametric generation or oscillation at infrared wavelengths. Planned simulations of our complex three-dimensional propagation geometry will help optimize the design parameters and minimize the losses. For lithium niobate PBG waveguides his vector coupled-mode theory calculations predict that the second-harmonic and parametric generation output efficiency will be enhanced by two orders of magnitude over quasi-phase matched devices of the same length. His experiments are designed to test these results. Furthermore, he will explore the properties of 2D photonic crystals to further improve frequency generation based on the large dispersion, resonant field enhancement, and low group velocity, which is an ubiquitous feature of higher dimensional PBGs not related to a band edge. He will conduct a theoretical study of the resonant mode characteristics of 1D and 2D PBGs to determine the grating and waveguide fabrication issues and test the designs in the sample fabrication process. Photonic band gap structures have received wide attention because of their unique properties and potential for diverse applications. The coherent, PBG sources could impact future developments in storage technology, imaging, space communications, xerography, medical photo-therapy, bio-assays, and UV lithography. Students will be trained with the skills and knowledge to develop future PBG-based optoelectronic devices. They will fabricate and characterize the devices and test the accuracy of the designs by comparing with modeling and simulation results. Hence they will have developed a broad range of laboratory and modeling experien