Journal ArticleDOI
Double-grating thin-film devices based on second-order Bragg interaction
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TLDR
In this article, coupledmode equations describing the second-order Bragg interaction were derived for the transverse electric mode of a dielectric film waveguide with periodic corrugations on both the film cover and the film substrate interfaces.Abstract:
Four coupled‐mode equations describing the characteristics of the second‐order Bragg interaction are derived for the transverse electric mode of a dielectric film waveguide with periodic corrugations on both the film‐cover and the film‐substrate interfaces. The characteristics of the frequency‐selective filter, output coupler, input coupler, and distributed feedback laser are obtained. Proper choice of the design parameters leads to a frequency‐selective filter radiating neither in the cover nor in the substrate, a highly efficient output coupler radiating only in the cover, and an efficient input coupler exciting a guided wave only in one direction. Similarly, in the distributed feedback laser, a suitable choice of the parameters of the two gratings provides a mechanism for controlling the oscillation characteristics of the laser. The attractive feature of the double‐grating design is that the characteristics of the thin‐film devices are not very sensitive to small deviations of the grating parameters from their designed values.read more
Citations
More filters
Journal ArticleDOI
Resonant Dual‐Grating Metamembranes Supporting Spectrally Narrow Bound States in the Continuum
Hafez Hemmati,Robert Magnusson +1 more
Dissertation
Study of compact planar antennas for multi and wide band applications
Abstract: This thesis explores different compact planar antenna structures and their applicability in the field of microwave engineering. Miniaturized compact antennas that can provide wide bandwidth, multiple bands of resonance at desired frequencies, good return loss, high gain have always been in demand in the antenna industry. Keeping these desired aspects in mind, the work presented aims at proposing novel antenna designs that have improved performance characteristics in comparison to the ones reported in the literature till date. The overall contribution can be divided into three parts. In the first part, an analytical procedure called singular perturbation method has been performed for a double periodic transmission line structure with both inductance and capacitance modulated. The method has been employed to analyze a double periodic composite right/left handed (CRLH) leaky wave structure. Numerical expressions have been derived from which we have obtained the dispersion characteristics, propagation constant and radiation characteristics of the structure. We have also included the modulation of the permeability along with permittivity which increases the degree of freedom of the analysis. The radiation efficiency has been plotted as a function of antennas length to illustrate the effect of modulating indices on the antenna performance. The theoretical, simulated and the measured results seem to be in good agreement, thus justifying the application of the singular perturbation method on multiple scales for similar kind of structures. The next work proposes a novel leaky wave antenna design based on CRLH metamaterials which has been implemented on a substrate integrated waveguide(SIW) platform. It operates
Journal ArticleDOI
TM mode analysis in a metamaterial based dielectric waveguide
TL;DR: In this article, a TM mode analysis in a metamaterial based dielectric waveguide is proposed and introduced, and the dispersion properties are focussed on the fundamental properties of bound, surface and leaky modes of a waveguide.
Dissertation
Principles, design, fabrication, and characterization of subwavelength periodic resonant metasurfaces
Journal ArticleDOI
Second-order bragg interaction in double grating couplers: TM mode
TL;DR: An analytical treatment of the second-order Bragg interaction for the transverse magnetic mode of a dielectric film waveguide having gratings on both the film cover and the film-substrate interfaces is presented in this article.
References
More filters
Journal ArticleDOI
Carrier-induced change in refractive index of InP, GaAs and InGaAsP
TL;DR: In this article, the change in refractive index Delta n produced by injection of free carriers in InP, GaAs, and InGaAsP was theoretically estimated and the results were in reasonably good agreement with the limited experimental data available.
Journal ArticleDOI
Observation of destructive interference in the radiation loss of second-order distributed feedback lasers
TL;DR: In this article, the authors reported measurements of the distribution of 90° radiation loss along the length of an optically pumped distributed feedback resonator having a second-order grating and nonreflecting ends.
Journal ArticleDOI
Surface‐emitting distributed feedback semiconductor laser
S. H. Macomber,J. S. Mott,R. J. Noll,G. M. Gallatin,Edward J. Gratrix,S. L. O’Dwyer,S. A. Lambert +6 more
TL;DR: In this article, a single spatial mode device with low divergence output beams and single frequency spectra was demonstrated without any facet reflections, which contained second-order gratings etched into a thin p−AlGaAs cladding layer surface.
Journal ArticleDOI
Interference Phenomena in Waveguides with Two Corrugated Boundaries
TL;DR: In this paper, the anomalous light reflection from waveguides with two corrugated boundaries is considered and it is shown theoretically and experimentally that these structures can form the basis for a highly efficient unidirectional grating coupler for slab waveguide.
Journal ArticleDOI
High-efficiency single-order waveguide grating coupler.
TL;DR: High-efficiency single-order grating coupling between an optical waveguided mode and a volume wave is achieved by means of a double-sided corrugated cover film that has phase-shifted undulations.