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Properties Of The Quarter-Wave Bragg Reflection Waveguide: Theory, Brian R. West, Amr S. Helmy
Properties Of The Quarter-Wave Bragg Reflection Waveguide: Theory, Brian R. West, Amr S. Helmy
Physics and Computer Science Faculty Publications
The Bragg reflection waveguide (BRW), or one-dimensional photonic crystal waveguide, has recently been proposed for a wide spectrum of applications ranging from particle acceleration to nonlinear frequency conversion. Here, we conduct a thorough analytical investigation of the quarter-wave BRW, in which the layers of the resonant cladding have a thickness corresponding to one quarter of the transverse wavelength of a desired guided mode. An analytical solution to the mode dispersion equation is derived, and it is shown that the quarter-wave BRW is polarization degenerate, although the TE and TM mode profiles differ significantly as the external Brewster’s angle condition in …
Dispersion Tailoring Of The Quarter-Wave Bragg Reflection Waveguide, Brian R. West, Amr S. Helmy
Dispersion Tailoring Of The Quarter-Wave Bragg Reflection Waveguide, Brian R. West, Amr S. Helmy
Physics and Computer Science Faculty Publications
We present analytical formulae for the polarization dependent first- and second-order dispersion of a quarter-wave Bragg reflection waveguide (QtW-BRW). Using these formulae, we develop several qualitative properties of the QtW-BRW. In particular, we show that the birefringence of these waveguides changes sign at the QtW wavelength. Regimes of total dispersion corresponding to predominantly materialdominated and waveguide-dominated dispersion are identified. Using this concept, it is shown that the QtW-BRW can be designed so as to provide anomalous group velocity dispersion of large magnitude, or very small GVD of either sign, simply by an appropriate chose of layer thicknesses. Implications on nonlinear …
A Note On Quasi-Triangulated Graphs, Ion Gorgos, Chính T. Hoàng, Vitaly Voloshin
A Note On Quasi-Triangulated Graphs, Ion Gorgos, Chính T. Hoàng, Vitaly Voloshin
Physics and Computer Science Faculty Publications
A graph is quasi-triangulated if each of its induced subgraphs has a vertex which is either simplicial (its neighbors form a clique) or cosimplicial (its nonneighbors form an independent set). We prove that a graph G is quasi-triangulated if and only if each induced subgraph H of G contains a vertex that does not lie in a hole, or an antihole, where a hole is a chordless cycle with at least four vertices, and an antihole is the complement of a hole. We also present an algorithm that recognizes a quasi-triangulated graph in O(nm) time.
Genetic Algorithm For Orthogonal Designs, Jason Cousineau, Ilias S. Kotsireas, Christos Koukouvinos
Genetic Algorithm For Orthogonal Designs, Jason Cousineau, Ilias S. Kotsireas, Christos Koukouvinos
Physics and Computer Science Faculty Publications
We show how to use Simple Genetic Algorithm to produce Hadamard matrices of large orders, from teh full orthogonal design or oder 16 with 9 variables, OD(16; 1, 1, 2, 2, 2, 2, 2, 2, 2). The objective functionthat we use in our implementation of Simple Genetic Algorithm, comes from a Computational Algebra formalism of the full orthogonal design equations. In particular, we constructed Hadamard matrices of orders 144, 176, 208, 240, 272, 304 and 336, from the aforementioned orthogonal design. By varying three genetic operator parameters, we computer 62 inequivalent Hadamard matices of order 304 and 4 inequivalent …