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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Development of a novel balloon-borne optical sonde for the measurement of ozone and other stratospheric trace gases = Entwicklung einer ballongestützten optischen Sonde zur Messung von Ozon und anderen stratosphärischen Spurengasen /

Wolff, Mareile. January 2007 (has links)
Univ., Diss.--Bremen, 2005.
22

A polarized lateral shearing interferometer and application for on-machine form error measurement of engineering surfaces /

Liu, Xiaojun. January 2003 (has links)
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 96-104). Also available in electronic version. Access restricted to campus users.
23

A null-balance visual densitometer /

Baez, Ramon P. January 1987 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1987. / Typescript. Includes bibliographical references (leaves 29-30).
24

Model automatic focusing system for linewidth measuring instruments /

Ingraham, John. January 1985 (has links)
Thesis (B.S.)--Rochester Institute of Technology, 1985. / Typescript. Includes bibliographical references (leaves 31-32).
25

Testing chromatic adaptation models using object colors /

Pirrotta, Elizabeth. January 1994 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaves 80-84).
26

Rapid 3D measurement using digital video cameras /

Van der Merwe, Willem Johannes. January 2008 (has links)
Thesis (MScEng)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
27

Investigation of a multi-purpose optical measurement system /

He, Zaiqian. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 65-68). Also available in electronic version.
28

Robust position measurement in visual eigenspace /

Quick, Philip George. Capson, David W. January 1900 (has links)
Thesis (Ph.D.)--McMaster University, 2003. / Advisor: David Capson. Includes bibliographical references (leaves 202-207). Also available via World Wide Web.
29

Efficient finite element modeling across optical length scales

Harwood, Jason Alan. January 2007 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Christopher H. Jenkins. Includes bibliographical references (leaves 60-61).
30

Single-end reflectometric measurements of polarization-mode dispersion in single-mode optical fibres

Fosuhene, Samuel Kofi January 2013 (has links)
In this thesis two novel single-end methods are applied to measure and characterize polarization mode dispersion in single mode optical fibres. Polarization mode dispersion (PMD) is an important factor negatively affecting the successful implementation of high speed long haul optical fibre networks operating at bit rates of 10Gb/s and above. PMD measurements are thus important for quality control during manufacturing and cabling processes. It is also useful for network operators planning to upgrade bitrates in existing networks to 10Gb/s and beyond. In an optical fibre link, sections with particularly high PMD may act to increase the entire PMD of the link. Identifying and replacing such sections can greatly reduce the PMD of the link. PMD measurements can be forward or single-end. In forward measurements, both ends of the fibre are used for input and detection. In single-end configuration, only one end of the fibre is used. For this reason, single-end measurements are more practical for the field where fibre ends are situated several kilometres apart. Single-end techniques can be implemented with a continuous wave for non-local PMD measurements (by Fresnel reflection). If a pulsed wave is used, local measurements can be achieved (by total power due to Rayleigh scattering). Two single-end schemes, one based on Fresnel reflection and the other due to Rayleigh scattering have been applied to measure non-local and local PMD of standard single mode optical fibres. For the non-local PMD measurements, the general interferometric technique (GINTY) was modified to operate in a round-trip configuration. In this configuration, the fibre was treated as a concatenation of two identical fibre segments. Three different sets of fibres were investigated, each set representing a particular mode coupling regime. For polarization maintaining fibres, (PMFs), with no mode coupling, a factor of two was found between forward and single-end measurements. For long single mode fibres in the long length regime, the factor was 1.4. For a combination of PMF and single mode fibres, a factor of 1.6 was obtained. The method which is accurate, repeatable, low cost and robust is very suitable for field applications. The second method is the polarization optical time domain reflectometric (P-OTDR) technique. This technique performs local birefringence measurements by measuring the evolution of the states of polarization (SOP). The birefringence information from such measurements was extracted and analysed to characterise four different fibres. Beat lengths and correlation lengths extracted from the P-OTDR were used to calculate the differential group delay (DGD) of the fibres. Next an expression for the root-mean-square differential group delay was derived and applied to the birefringence measurements to calculate the DGDs at a single wavelength. This method which operates at a single wavelength has a huge advantage. Firstly it is able to measure completely all the fibre characteristic parameters. Secondly it can measure mean DGD, root mean square DGD and instantaneous DGD. A plot of instantaneous DGD vs. length enables one to identify and eliminate sections with particularly high DGD. Finally since the P-OTDR system operates with a single wavelength, real time monitoring of PMD is possible via multiplexing. The results obtained are repeatable, accurate and are in good agreement with the standard Jones Matrix Eigenanalysis (JME) technique.

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