Search for dissertations about: "optical lattice"

Showing result 1 - 5 of 120 swedish dissertations containing the words optical lattice.

  2. 1. Signaling for Optical Intensity Channels

    Author : Johnny Karout; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lattice codes; mutual information; intensity modulation; noncoherent communications; Direct detection; sphere packing.; infrared communications; free-space optical communications; fiber-optical communications;

    Abstract : With the growing popularity of social media services, e-commerce, and many other internet-based services, we are witnessing a rapid growth in the deployment of data centers and cloud computing platforms. As a result, the telecommunications industry has to continue providing additional network capacity to meet the increasing demand for bandwidth. READ MORE

  4. 2. Atomic transport in optical lattices

    Author : Henning Hagman; Claude Dion; Daniel Comparat; Umeå universitet; []
    Keywords : Ultra-cold atoms; optical lattice; laser cooling; directed transport; Brownian motor; Brownian motion;

    Abstract : This thesis includes both experimental and theoretical investigations of fluctuation-induced transport phenomena, presented in a series of nine papers, by studies of the dynamics of cold atoms in dissipative optical lattices. With standard laser cooling techniques about 108 cesium atoms are accumulated, cooled to a few μK, and transferred into a dissipative optical lattice. READ MORE

  5. 3. Modulation Optimization for Noncoherent Optical Systems

    Author : Johnny Karout; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct detection; noncoherent communications; lattice codes; mutual information; fiber-optical communications; intensity modula- tion; sphere packing.; infrared communications; free-space optical communications;

    Abstract : There has been a significant improvement in high-speed electronics and optical components over the past few years, and this is one of the key enabling factors for high data rate transmission. Moreover, multi- level modulation formats, which encode information onto the carrier’s amplitude and phase, are necessary to increase the spectral efficiency of communication systems. READ MORE

  6. 4. Multidimensional Constellation Shaping for Coherent Optical Communication Systems

    Author : Ali Mirani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lattice-based constellations; geometric shaping; probabilistic shaping; multidimensional modulation format; Voronoi constellation; constellation shaping; optical communications; coherent receiver;

    Abstract : To overcome the increasing demands for Internet traffic, exploiting the available degrees of freedom in optical communication systems is necessary. In this thesis, we study how constellation shaping can be achieved in various dimensions and how various shaping schemes affect the whole performance in real systems. READ MORE

  7. 5. Nanostructured Semiconductor Materials for Light Manipulation Functions

    Author : Dennis Visser; Srinivasan Anand; Alvaro Blanco; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor materials; c-Si; a-Si; GaInP; TiO2; ZnO; nanostructuring; light manipulation functions; top-down fabrication; embossing; FDTD simulations; nanowires; nanopillars; nanodisks; microcones; optical response; reflectance; transmittance; absorbance; spectrophotometry; photoluminescence; Mie resonators; mode coupling; broadband anti-reflection; light extraction enhancement; optical sensing; optical color filters; color conversion; Optik och fotonik; Optics and Photonics;

    Abstract : Structuring of semiconductor materials is utilized in many optoelectronic devices, e.g, in order to make them more efficient, cost-effective, and/or to obtain specific wavelength-engineered responses. Semiconductor materials are widely used in optoelectronic devices due to their favorable optical and electric properties. READ MORE