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Design, fabrication and characterisation of polymer based wavelength-division-multiplexing filters for fibre-to-the-home applicationHao, Ying January 2012 (has links)
No description available.
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Optical multicast radio-over-fibre distributed antenna systemFang, Ke January 2012 (has links)
No description available.
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Design of a biomimetic acoustic sensorMarshall, Heather K. 05 1900 (has links)
No description available.
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Multi-Parameter Sensing Based On In-Line Mach-Zehnder InterferometerXu, Yanping 04 September 2013 (has links)
Optical fiber sensors have been intensively studied and successfully employed in various human social activities and daily living, such as industrial production, civil engineering, medicine, transportation, national defense and so on. According to different structures, optical sensors could be divided into various categories. This thesis focuses on studying different kinds of in-line fiber Mach-Zehnder interferometers, which have played an important role among the optical interferometric fiber sensors. The structure composition, fabrication process, physical principle and practical applications of two novel in-line fiber Mach-Zehnder interferometers are proposed and discussed in detail in this work.
The tapered bend-insensitive fiber Mach-Zehnder interferometer (BIF-MZI) is firstly fabricated and used as a fiber vibrometer. The unique double-cladding structure of bend-insensitive fiber not only provides higher mechanical strength to the sensor, but also guarantees a more uniform transmission spectrum, since only a few inner-cladding modes are left interfering with the core mode. A high sensitivity and fast response intensity demodulation scheme is employed by monitoring the power fluctuation of the BIF-MZI at the operation wavelength. Both damped and continuous vibrations are detected using the proposed sensor. It is demonstrated that this sensor responses to an extremely wide range of frequencies from 1 Hz up to 500 kHz with high signal-to-noise ratios (SNRs).
The discrimination of temperature and axial strain is realized based on the dispersion effects of high-order-mode fiber (HOMF) by forming a single mode fiber-high-order-mode fiber-single mode fiber (SMF-HOMF-SMF) structure based in-line Mach-Zehnder interferometer. Unlike some kinds of in-line MZIs such as tapered and core–offset structures whose cladding modes are excited with different types under changing temperature and strain circumstances, the HOMF is capable of supporting three stable core modes, which guarantees a reliable and repeatable measurements within a large temperature or strain range. A new method based on the fast Fourier transform (FFT) is employed to analyze the mode couplings and their chromatic dispersion and intermodal dispersion properties in HOMF. The strong dispersion effects lead to a multi-peak feature in the spatial frequency spectrum. It is found that peaks that denote the waveform periods at positions that are beyond the critical wavelength possess highly sensitive and distinct phase responses to external disturbances, which provides the possibility to realize the discrimination measurements with high sensitivities and smaller errors by selecting appropriate peaks. The phase demodulation scheme is applied to quantify the temperature and strain changes in terms of phase shifts. Appropriate peak selections according to the practical needs would provide an easy access for applications where more than two parameters are required to be discriminated.
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Fibre-optic sensing technology and applications in civil engineering.Wong, Allan Chi-Lun, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2007 (has links)
This thesis reports the research and industry-related works carried out from the development of a fibre-optic strain sensor system for Civil Engineering applications. A sensor system consists of a number of core components, including the sensing element, interrogation/demodulation, multiplexing, signal processing and hardware equipment. In the process of development, a number of issues have been identified and investigated, which resulted in the improvement of the system performance, as well as the proposal of new techniques for the sensor system. First, an improved demodulation technique for a type of sensor, namely the fibre Fizeau interferometer (FFI), is presented. The technique is based on the improvement of the Fourier transform peak detection method, which suffers severely from the poor resolution and accuracy of finding the sensor cavity length. The improvement over the original method has been compared and verified through simulations and experiments. Second, a simultaneous demodulation technique for multiplexed FFI and fibre Bragg grating (FBG) sensors using the discrete wavelet transform (DWT) is proposed. Third, a multiplexing technique using amplitude-modulated chirped FBGs and the DWT is proposed. These two proposed techniques have been demonstrated experimentally through strain measurements. The strain resolution, crosstalk and limitations are investigated. In addition, simultaneous quasi-static strain and temperature sensing of different metal plates are performed. Fibre-optic sensors have found numerous applications in different areas. In this thesis, the use of FBG sensors in Civil Engineering applications is demonstrated in four experimental studies, including: (i) long-term measurement of drying shrinkage and creep of structural grade concrete; (ii) simultaneous measurement of shrinkage and temperature of reactive powder concrete (RPC) at early-age; (iii) measurement of coefficients of thermal expansion of cement mortar and RPC; and (iv) field-trial on the strain monitoring of the world?s first RPC road bridge. In addition, the experimental and practical issues of using FBG sensors are considered.
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Fabrication of long-period fiber gratings by CO₂ laser irradiation for high temperature applicationsWei, Tao, January 2008 (has links) (PDF)
Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 31, 2008) Includes bibliographical references (p. 33-36).
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Cross-reactive fiber-optic sensor arrays in the design of an artificial nose /Dickinson, Todd A. January 1900 (has links)
Thesis (Ph.D.)--Tufts University, 1999. / Adviser: David R. Walt. Submitted to the Dept. of Chemistry. Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Some issues in magnetostrictive fiberoptic sensors /Rojas, Rafael. January 1900 (has links)
Thesis (Ph.D.)--Tufts University, 2001. / Adviser: Chris Davis. Submitted to the Dept. of Electrical Engineering. Includes bibliographical references (leaves 94-101). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Fiber optic MOD smart fabric detector arrays for spacecraft applications.Rethoret, Brian. January 2006 (has links)
Thesis (M.A. Sc.)--University of Toronto, 2006. / Source: Masters Abstracts International, Volume: 44-06, page: 2869. Includes bibliographical references.
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Factors related to the adoption of a two-way interactive distance education technology instrument development, instrument validation, and causal model testing /Abou-Dagga, Sanaa Ibrahim. January 1995 (has links) (PDF)
Thesis (Ph.D.)--Iowa State University, 1995. / Includes bibliographical references (leaves 104-111).
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