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A comparison of design techniques for gradient-index thin film optical filters

  • Authors: Kotze, Abraham Paulus
  • Date: 2012-08-08
  • Subjects: Thin film devices , Thin films - Optical properties , Fiber optics , Fourier transformations , Maxwell equations , Wavelets (Mathematics)
  • Type: Thesis
  • Identifier: uj:8984 , http://hdl.handle.net/10210/5453
  • Description: M.Ing. , This work comprises the implementation and comparison of five design techniques for the design of gradient-index thin film optical filters: classical rugate, inverse Fourier transform, a wavelet-based design procedure, as well as the flip-flop and the genetic optimization techniques. Designs for a high-reflectance filter, a beamsplitter, a discrete level filter, a distributed filter, and an anti-reflection coating were used to compare the various filter synthesis techniques. The optical thickness of the various examples was maintained below 30 and the refractive index excursion limits were between 1.5 and 3.2. The overall performance of a specific design was evaluated by a weighted merit function. The classical rugate filter uses a sinusoidal refractive index modulation that produces a single reflection band. More complex filters are realized by linear superposition of these elementary profiles. Sidelobe and ripple suppression are obtained by applying quintic windowing functions to the refractive index profile and adding matching layers at the edges of the filter. This filter design procedure has the best figure of merit of 3.73 for the discrete level filter, and the second best of 3.09 for the high-reflectance filter. The inverse Fourier transform links the refractive index profile and reflection spectrum of an optical filter by an approximate relation. It is self-correcting and iterative in nature. It produces filters with the highest optical density. The procedure excels in the design of the distributed filter with a figure of merit of 4.17. Mortlett's wavelet is used as the basis of the wavelet design technique. A single wavelet yields a single reflection band, similar to the classical rugate filter. Sidelobe suppression is an inherent property of the method, but matching layers are needed for passband ripple suppression. The optical density of the high reflection filter is larger for a filter designed with this method than for the equivalent classical rugate filter. The figure of merit of 1.75 for the high-reflectance filter is the best for any of the designs. Flip-flop refinement is a brute force approach to filter design. The layers of a starting design are flipped between two values of refractive index, the change in figure of merit evaluated and the best case saved. This process is repeated for a fixed number of iterations. It is computationally intensive and lacks ripple suppression characteristics. The flip-flop method does not compare well with any of the other techniques. It yields filters with the worst figures of merit for most of the design examples. However, it was applied successfully to the anti-reflection coating. The peak ripple for the anti-reflection filter in the 400 nm to 1100 nm wavelength band is 9.62 % compared to the inverse Fourier transform's 57.30 %. The genetic algorithm operates on the principle of "survival of the fittest". It is a stochastic procedure and yields quasi-random refractive index profiles. It excels with the antireflection coating. The peak ripple in the passband of the anti-reflection coating is 3.29%. The figure of merit for the anti-reflection coating designed with the genetic algorithm is 2.09.
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Manufacturing of azimuthally symmetric long-period fibre gratings using a CO2 laser

  • Authors: Kritzinger, Ronnie
  • Date: 2012-08-27
  • Subjects: Optical communications , Optical fiber detectors , Fiber optics
  • Type: Thesis
  • Identifier: uj:3268 , http://hdl.handle.net/10210/6675
  • Description: M.Ing. , The development of fibre optic technology as we know it today, has taken a giant leap forward since the introduction of Internet technology and other telecommunication devices. More recently, the need exists to retrieve and send huge amounts of data fast and efficiently by using fibre optic cable in computer networks, without the need of expensive equipment. Due to the large amounts of data (like video and audio) that has to be sent and received across a computer network at large distances, this dissertation is primarily concerned with the design and manufacturing of low-loss uniform long period fibre gratings for the realization of future optical add/drop multiplexers. An azimuthally symmetric manufacturing method is implemented using several optical components and devices. Several electronic devices are connected to a Mannesmann Rexroth ECODRIVE03 drive controller unit, and a computer control program was written in VISUAL BASIC 6.0 to control these devices during the manufacturing of these unique LPGs. A number of theories and numerical methods such as the coupled-mode theory and the transfer matrix method are applied in the analysis, modelling, and simulation of short/long-period fibre gratings. Simulation results were obtained in MATLAB 6.5 and the code was written in such a way that the end user could simulate any short/long-period grating and obtain the necessary results such as the transmission spectra, time delay and dispersion for uniform fibre gratings. These simulations obtained were a good indication on how the experimental results should look after manufacturing the unique symmetric LPGs.
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An Object-oriented simulation program for fibre bragg gratings

  • Authors: Zhao, Jianfeng
  • Date: 2009-02-27T06:02:43Z
  • Subjects: Fiber optics , Simulation methods
  • Type: Thesis
  • Identifier: uj:8184 , http://hdl.handle.net/10210/2189
  • Description: M.Ing. , In recent years, many research and development projects have focused on the study of fibre Bragg gratings. Fibre Bragg gratings have been used in the field of sensors, lasers and communications systems. Commercial products that use fibre Bragg gratings are available. On the other hand, in the field of software development, object-oriented programming techniques are also becoming very popular and powerful. The focus of this work is on solving fibre Bragg grating problems by a simulation program with object-oriented programming techniques. For fibre Bragg grating problems, widely used theories and numerical methods such as the coupled-mode theory and the transfer matrix method will be applied in the analysis, modelling and simulation. The coupled-mode theory is a suitable tool for analysis and for obtaining quantitative information about the spectrum of a fibre Bragg grating. The transfer matrix can be used to solve non-uniform fibre Bragg gratings. Two coupled-mode equations can be obtained and simplified by using the weak waveguide approximation. The spectrum characteristics can be obtained by solving these coupled-mode equations. The optical numerical libraries of fibre Bragg gratings have been built by using object-oriented techniques. The code was realized by C++ and Object Pascal language in the Delphi4, C++ Builder4 and Visual C++6 environment. The compiled binary files and the code of the simulation program are available for both the end user and program developer. This simulation program can be used to analyze the performance of sensors and communication systems that use fibre Bragg gratings. Uniform, chirped, apodized, discrete phase shifted and sampled Bragg gratings have already been simulated by using the direct numerical integration method and the transfer matrix method. The reflected and transmitted spectra, time delay and dispersion of fibre Bragg gratings can be obtained by using this simulation program. At the same time, the maximum reflectivity, 3dB-bandwidth and centre wavelength can also be obtained. This thesis consists of three parts. The first part introduces a suitable theory and modelling that have been used to analyze the characteristics of fibre Bragg gratings. Secondly, the codes of the modelling are realized by the suitable programming languages in different development environments. Finally, this simulation program is utilized to analyse real physical problems with fibre Bragg grating applications.
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Eksperimentele ondersoek na die vervaardiging van enkele stelselkomponente vir 'n hidrofoon in optiese veseltegnologie

  • Authors: Spammer, Stephanus Johannes
  • Date: 2015-02-25
  • Subjects: Fiber optics , Optical fibers , Hydrophone
  • Type: Thesis
  • Identifier: uj:13348 , http://hdl.handle.net/10210/13362
  • Description: M.Ing. , A study was done on optical fibre hydrophones. Integrated optic hydrophone components as well as optical fibre components were investigated. An optical fibre coupler was successfully manufactured with an etch process. The coupling ratio can be varied mechanically or by means of refraction index variation. Experimental procedures and results will be shown. Bending losses excited in an optical fibre coil were investigated as a function of different coil diameters. The results were extrapolated to determine the amount of losses arising in a hydrophone coil.
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Development, characterisation and analysis of an active Q-switched fiber laser based on the modulation of a fiber Fabry-Perot tunable filter

  • Authors: Monga, Kaboko Jean-Jacques
  • Date: 2018
  • Subjects: Fiber optics , Lasers
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/286074 , uj:30948
  • Description: D.Phil. (Electrical Engineering) , Abstract: The field of fiber lasers and fiber optic devices has experienced a sustained rapid growth. In particular, all-fiber Q-switched lasers offer inherent advantages of relatively low cost, compact design, light weight, low maintenance, and increased robustness and simplicity over other fiber laser systems. In this thesis, a design of a new Q-switching approach in all-fiber based laser is proposed. The Q-switching principle is based on dynamic spectral overlapping of two filters, namely fiber Bragg grating based filter and fiber Fabry-Perot tunable filter. When the spectra overlap, the filter system has the maximum transparency, the laser cavity has minimal losses and it can release the stored power in the form of the giant pulse. Using this Q-switching technique, experimental construction of an all-fiber active Q-switched Erbium-doped fiber lasers is successfully demonstrated in both ring cavity and linear cavity fiber laser configurations. The output peak power of 9.7 W and time duration of 500 ns are obtained at 1 kHz of repetition rate for ring cavity Q-switched Erbium-doped fiber laser; and 5.6 W output peak power with a 450 ns pulse time duration are achieved for linear cavity Q-switched Erbium-doped fiber laser at the same repetition rate. The repetition rate of the pulses can be continuously varied from a single shot to a few kHz...
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An investigation into performance criteria for Fibre Bragg Grating sensors embedded in composite structures

  • Authors: Roberson, Craig Valentine
  • Date: 2014-09-17
  • Subjects: Bragg gratings , Fiber optics , Diffraction gratings
  • Type: Thesis
  • Identifier: uj:12338 , http://hdl.handle.net/10210/12124
  • Description: M.Ing. (Mechanical Engineering) , The dissertation explores the applications and limitations of optic Fibre Bragg Grating (FBG) sensors for the purpose of structural health monitoring of high performance composite aerospace structures. The absence of a set of stringent performance criteria governing the form and function of a sensory system for embedded high performance applications highlights the major hurdle to be overcome before widespread acceptance of these technologies becomes apparent. The dissertation therefore develops through an extensive literature study a basic framework of performance criteria to be met by the sensory system upon which a prototype Structural Health Monitoring (SHM) system can be further developed. The resolution of the performance criteria into categories of mechanical and non-mechanical performance allows independent evaluation of factors that directly affect the performance of the sensor (in terms of strength, embeddability and load carrying ability) as well as its functional performance (in terms of orientation, spatial resolution and measurement philosophy). The literature study uses the non-mechanical performance limitations as a guideline for the selection of Fibre Bragg Grating (FBG) sensors as the sensory mechanism. The mechanical performance limitations of these specific sensors are then called into question and evaluated. Independent experiment campaigns are therefore developed to evaluate the mechanical and non-mechanical performance limitations such that a set of performance criteria can be developed governing the use of embedded sensory systems. Non mechanical performance with particular emphasis on sensor placement and orientation is investigated by simulating a fixed-free Euler Bernoulli cantilever using the Finite Element Method (FEM). The ability of the sensor to identify structural changes by measuring changes in modal response shows good results. Furthermore the inability of modal based monitoring to identify structural changes in the vicinity of modal inflection points is identified as an opportunity to locate structural deficiencies by monitoring multiple modes with known inflection point positions. The method also provides recommendations of sensor placement and orientation (close to the beam fixture and parallel with the neutral axis) such that the effectiveness of strain component measurements from all measurable modes is maximised. Mechanical performance of embedded FBG sensors is evaluated through an extensive fracture testing program which measures the fracture strains of fibre samples subjected to two-point bending. The fracture test program allows the quantification of the effects of the presence of the fibre’s protective polymer coating on fibre embeddability in composites, the consequent effects that the removal of this coating has on the mechanical performance and fracture behaviour of FBG sensors. These effects are qualified and mitigatory measures developed to improve the mechanical performance. A system of crack masking, hydrofluoric acid etching and fibre treatment is developed and statistical data analysis methods are employed and refined such that improvements in the mechanical properties of the FBG sensors can be quantified. An evaluation of the effectiveness of the proposed mechanical performance improvements yields good results culminating in the development of a comprehensive set of mechanical performance criteria to facilitate further development of a reliable SHM system.
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A phase detection system with enhanced dynamic response for open-loop fibre-optic gyroscopes

Improving the reliability of smart grids through the use of fiber optical communication

  • Authors: Nthate, Sanah
  • Date: 2017
  • Subjects: Optical fiber communication , Fiber optics , Smart power grids
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/262604 , uj:27726
  • Description: M.Tech. (Electrical Engineering) , Abstract: In this research we determine ways to improve the reliability of smart grids through the use of fiber optical communication. We first explore the network requirements of smart grids in South Africa through qualitative interviews. The calculations and simulations were based on the following: how the signal level drops, the losses into the fiber optic systems connector and the splice losses while using fiber optical communication. The distance measured in kilometers was used to determine the fiber’s quality, loss per unit. The lower the loss per unit length, the stronger the signals at the receiving end. Fiber has proved its abilities of being the best communication network tool as it can transmit signal over long distances without being boosted or disturbed, its capacity is far greater and lighter and smaller than copper. The focus was on the reliability of smart grids through the use of Fiber optical communication. Qualitative interviews were conducted with experts from power companies also regarding wired and wireless networks used. The interviews also revealed that Fiber optical communication can give accurate real time data when connected to smart grids. Some interviewees, who were in power companies, were not familiar with fiber optical communication and ZigBee wireless communication network. Comprehensive calculations were performed to confirm the effectiveness of fiber optical communication. ZigBee like any other wireless proved that it has its own weakness by not being reliable as it can be easily tampered or easily disturbed by natural circumstances, natural forces and natural structures. We determine fiber optical communication’s reliability in terms of their rates distances, coverages and data. The tests and simulations that were conducted using fiber optical communication Optical Time Domain Reflectometer (OTDR) showed that the reliability of the fiber that can be used for smart grid.
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Characterization of Bragg grating pressure sensor using finite element analysis theory and experimental results

  • Authors: Van Niekerk, Wynand F.
  • Date: 2010-10-04T08:55:31Z
  • Subjects: Bragg gratings , Fiber optics , Pressure transducers , Finite element method
  • Type: Thesis
  • Identifier: uj:6925 , http://hdl.handle.net/10210/3435
  • Description: M.Ing. , Optical fibre Bragg gratings are a periodic variation of the refractive index in the core of an optical fibre andmay be formed by exposure to intense UV laser light under specific conditions. Light at a certain wavelength, called the Bragg wavelength, is reflected back when illuminating the grating with a light source. Bragg gratings can relatively easily be employed as strain and temperature sensors, but have small sensitivity for pressure. Special transducers are required to increase the sensitivity. A pressure sensor was manufactured by coating a fibre Bragg grating with a polymer. The polymer coating converts transverse pressure into longitudinal strain through the Poisson effect inside the polymer coating. This thesis investigates the sensitivity of themanufactured Bragg grating pressure sensor, by using the method of finite element analysis. An account of the experimental setup, whereby the Bragg grating is written with a frequency tripled Nd:YAG laser, is given. The process whereby the fibre is coated with the polymer is described. The sensor is characterized through experimental results and a comparison is made between theoretical and experimental results. Uses for this sensor and ways with which the sensitivity may be increased are suggested as future work.
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Numerical modelling of an Erbium-Ytterbium co-doped distributed feedback fiber laser

  • Authors: Mpoyo, Justice Sompo
  • Date: 2015-06-26
  • Subjects: Erbium , Fiber optics , Optical communications , Bragg gratings
  • Type: Thesis
  • Identifier: uj:13635 , http://hdl.handle.net/10210/13815
  • Description: M.Phil. (Electrical and Electronic Engineering) , A numerical model of an Erbium-Ytterbium co-doped distributed feedback (DFB) fiber laser is developed. The DFB fiber laser is a short length fiber laser whose feedback is distributed throughout the cavity. Its main advantage is its single longitudinal mode operation. The amplifying medium of a DFB fiber laser is a few centimetres long rare earth doped fiber. The feedback is obtained by a fibre Bragg grating printed in the core of the rare earth doped fiber. This type of laser emits naturally in two longitudinal modes. To obtain the single longitudinal mode operation, a π phase shift is introduced in the middle of the grating. Erbium doped DFB fiber lasers present the advantage of emitting single frequency light in the 1550 nm region where telecommunication fibers present the minimum loss. However due to the relatively short length of the gain medium, the number of available Erbium ions is small; as a result pump power absorption is low and the efficiency of the fiber laser is strongly reduced. The straightforward solution to this problem could be increasing the concentration of Erbium ions. This solution however has the disadvantage of increasing the Erbium ions interactions, thus leading to detrimental effect like cooperative upconversion and excited state absorption, which in term reduce considerably the laser efficiency. The best solution is to use Ytterbium ions as sensitizers along with Erbium ions to enhance the pump absorption, hence the efficiency of the laser. A model of the DFB fiber laser is an indispensable tool for its design, because it allows one to predict characteristic behaviour that would be both difficult and costly to deduce in laboratory conditions. The model developed in this project is based on rate equations of the Er3+-Yb3+ gain medium and coupled mode equations describing the laser field propagation in the fibre Bragg grating structure. The equations are solved using a quasi-analytical iterative method along with transfer matrix method with appropriate boundary conditions. The quasianalytical method used in this thesis is more robust than numerical solutions because it does not require providing an initial guess on the solution. Furthermore this method is hundreds time faster than the exact numerical solution while giving almost similar results.
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Veseloptiese koppelaars : vervaardiging en sensortoepassings

  • Authors: Booysen, André
  • Date: 2014-04-10
  • Subjects: Fiber optics
  • Type: Thesis
  • Identifier: uj:10553 , http://hdl.handle.net/10210/10079
  • Description: M.Ing. , This thesis covers the theory and development of fused, biconically tapered, fibre-optic couplers and their application in sensors. The optical coupling between fibres is described by means of the coupled-mode theory in the case of a weakly guiding coupler. Firstly, simplified expressions for the guided modes in an optical fibre are derived. This is followed by the derivation of the coupled-mode equations for a perturbed waveguide. The coupled-mode equations are then used, together with the expressions for the guided modes, to determine the coupling coefficient for a weakly guiding coupler. In the case where the coupler is not weakly guiding, a model based on a rectangular dielectric waveguide is presented. A process for the manufacture of fibre-optic couplers, based on the fusion and elongation technique, was developed. This process is described and special attention is paid to the influence which different process parameters has on the properties of the couplers. During the development, the coupling theory was utilized to optimize the process. Results obtained with couplers manufactured by this process, are presented. A specific application of couplers, namely a new type of fibre-optic coupler sensor, was developed. The operation of the sensor relies on the change of the coupling ratio with an axially applied mechanical strain. Analog signal processing of the two outputs yields a signal which is directly proportional to the strain and which is independent of fluctuations of the light source power. The sensor was investigated experimentally by manufacturing temperature and elongation sensors which work on this principle. The operation and features of these sensors are presented, together with very promising experimental results.
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Non-polarised edge filter design using genetic algorithm and its fabrication using electron beam evaporation deposition technique

  • Authors: Ejigu, Efrem Kebede
  • Date: 2013-11-25
  • Subjects: Fiber optics , Fourier transform optics , Genetic algorithms
  • Type: Thesis
  • Identifier: uj:7791 , http://hdl.handle.net/10210/8685
  • Description: D.Phil. (Electrical & Electronic Engineering Science) , Recent advancement in optical fibre communications technology is partly due to the advancement of optical thin-film technology. The advancement of optical thin-film technology includes the development of new and existing deposition and optical filter design methods. Genetic algorithm is one of the new design methods that show promising results in designing a number of complicated design specifications. The research is entirely devoted to the investigation of the genetic algorithm design method in the design of producible polarised and non-polarised edge filters for optical fibre communication applications. In this study, a number of optical filter design methods such as Fourier Transform and refining are investigated for their potential in designing those kinds of structures. Owing to the serious limitations to which they are subject, they could not yield the kind of results anticipated. It is the finding of this study that the genetic algorithm design method, through its optimisation capability, can give reliable and producible designs. This design method, in this study, optimises the thickness of each layer to get to the best possible solution. Its capability and unavoidable limitations in designing polarised and non-polarised beam splitters, edge filters and reflectors from absorptive and dispersive materials are well demonstrated. It is observed that the optical behaviour of the non-polarised filters designed by this method show a similar trend: as the angle of incidence increases the inevitable increase in the percentage of polarisation, stop bandwidth and ripple intensity is well controlled to an acceptable level. In the case of polarised designs the S-polarised designs show a better response to the optimisation process than the P-polarised designs, but all of them are kept well within an acceptable level. It is also demonstrated that polarised and non-polarised designs from the genetic algorithm are producible with great success. This research has accomplished the task of formulating a computer program using genetic algorithm in a Mathlab® environment for the design of producible polarised and non-polarised filters from materials of absorptive and dispersive nature.
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Towards the fabrication of polymer optical fibre Bragg gratings at 980 nm

  • Authors: Terblanche, Johannes Theodorus
  • Date: 2012-09-10
  • Subjects: Fiber optics , Bragg gratings
  • Type: Thesis
  • Identifier: uj:9908 , http://hdl.handle.net/10210/7307
  • Description: M.Ing. , Bragg gratings written in polymer optical fibres are much more sensitive to temperature and strain measurements than silica fibre with a lower Young's modules and higher temperature coefficient. The good biocompatibility of polymer fibres makes them ideal medical sensors for in vivo strain and temperature measurements as well as excellent chemical sensors that can easily be doped with organic compounds. Most of the Bragg gratings in polymer optical fibres are inscribed around 1550 nm where the attenuation is as large as 1 dB/em. Grating fabrication was investigated at 980 nm where the attenuation was discovered to be optimal (less than 0.1 dB/em). The polymer optical fibre was spliced to silica optical fibre through butt-coupling and affixed with optical adhesive to produce transmission loss of between 7 and 25 dB (at 980 nm). Preliminary results show that it may be possible to create fibre Bragg gratings in polymer optical fibre at 980 nm. Gratings inscribed in fibre with an energy density of between 80 and 150 mJ/cm2 supplied by Paradigm Optics (MORFOP3) had a repeatability of 25%. With the fibres supplied by Prof. Peng (PBzMA- PEMA- PMMA co-polymer) a success rate of more than 90% was achieved when using energy densities around 70 mJ/cm2 • However, these gratings were weak and disappeared within 48 hours. The strength of these gratings varied from grating to grating. The reason of this instability is unknown and should be further investigated. The temperature sensitivity of polymer optical fibre at 976 nm was found to be -100 ±17 pm;oc corresponding with the reported value of -94 pm;oc at 976 nm.
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Distributed temperature sensing and non-contact torsion measurement with fibre bragg gratings

  • Authors: Kruger, Ludi
  • Date: 2009-02-26T12:20:38Z
  • Subjects: Fiber optics , Optical fiber detectors , Temperature measurements , Torsion measurement
  • Type: Thesis
  • Identifier: uj:8163 , http://hdl.handle.net/10210/2169
  • Description: M.Ing. , This thesis demonstrates the measurement of temperature distribution across a metal plate and the non-contact measurement of torsion in a rotating shaft. After a thorough theoretical study of the origin of fibre Bragg gratings, methods of fabrication and erasing of gratings, methods of demodulating the signals from gratings, and methods of discriminating between strain and temperature variations in gratings, simulations and experiments were done to prove the feasibility of both temperature distribution measurement and non-contact torsion measurement. For the measurement of temperature distribution, a 450 x 450 x 1.6 mm type 304 stainless steel plate was used. Two 4,7Ω 25W resistors were used as heat sources, and five fibre Bragg gratings measured the temperature at strategic points on the plate. The measured values were interpolated appropriately and a three-dimensional representation of the temperature distribution was shown on a personal computer monitor. The measurement of torsion was first done on a non-rotating 25 mm diameter solid shaft with torque applied. Both resistive strain gauges and fibre Bragg gratings were attached to the shaft and the measurement results compared well. Up to 90 Nm of torque was applied to the shaft. The non-contact measurement of torsion on a rotating shaft was done with fibre Bragg gratings and involved the use of graded index (GRIN) lenses for transmitting optical information between the light source, the gratings, and back to the spectrum analyser through free space. A special Böhler steel with high yield strength was used, and the set-up was mounted on a lathe. The one end of the shaft was clamped in the lathe chuck, and the other was fixed to an automobile drum brake system, allowing the application of torque on the rotating shaft. Up to 97 Nm of torque was applied to the shaft rotating at 190 rpm, and the results are within 10% of the expected values. As far as we are aware, this is the first time that torsion is measured by fibre Bragg gratings without the need to have physical contact with the shaft, i.e. slip rings, to transmit the information to and from the sensors. The experimental results of this thesis confirm that fibre Bragg grating sensors can be applied usefully in temperature distribution measurement, as well as in the measurement of torsional stress in rotating shafts.
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Fibre optic network : cost factor comparison for broadband access in South African rural areas

  • Authors: Mamabolo, Solomon
  • Date: 2019
  • Subjects: Fiber optics
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/297372 , uj:32417
  • Description: Abstract: Progress in communication applications has led to various advances in broadband technologies. The main reason is that modern applications require very fast data processing and transmission with low latency. Consequently, fibre optic based medium is seen as a medium that meets these stringent requirements. Fibre optic has many inherent advantages that allows it to handle high data demanding applications. Furthermore, although fibre optic access networks are present in urban areas, mostly in a form of FTTH (fibre to the home) architecture, these networks are not common in rural areas. The supposed challenges with fibre optic access network as a rural broadband access solution is attributed to the speculated high installation costs associated with long distance digging and trenching. As a result, the main research problem is that rural areas have low density of people and are remote, making it very difficult for service providers to achieve economy of scale amidst the speculated high network costs. The research objective is to assess the fibre optic network’s deployment costeffectiveness through a full lifecycle cost analysis in comparison with existing broadband technologies in these areas. The research will as a result conduct a full lifecycle costs analysis of both a fibre optic network and an existing rural wireless network in these areas. A full lifecycle cost analysis will be conducted from the network’s planning phase up to the retirement phase. This research aims to deliver knowledge on broadband network’s lifecycle cost’s status in South African rural areas. This knowledge will as a result benefit the telecommunication industry and community as a whole because it provides crucial knowledge on broadband network’s lifecycle costs in South African rural areas. Numerous scholars and interest groups have explored the supply side aspects of broadband provisioning, but with regard to the determination of costs, few studies have analysed in detail the lifecycle cost of broadband networks in rural areas. , M.Phil. (Engineering Management)
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Effective customer engagement in the open access opticfibre industry in South Africa

  • Authors: Sebothoma, Nkane Sydney
  • Date: 2020
  • Subjects: Fibers , Fiber optics , Fiber optic cables
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/453014 , uj:39976
  • Description: Abstract: The aim of the research was to improve the overall process and customer engagement techniques of the calls being made to the customers to increase revenue of the company by increasing the number of customers willing to have the optic-fibre activated by the end of the call. Customer service can be defined in so many ways. It can have a completely different meaning from company to company . This is because companies are structured differently; as a result the operational policies and other organizational structures that govern the operations and performance of the customer service structure of the company differ though they tend to pursue the same goal. This has put engineering management to play a very important role concerning this research. Some of the principles such as product development which focuses on improving sales, concepts such as rate of return (RoR) that governs the goals of the company and systems engineering which contributed in systematic approach on customer behaviour. The study was designed from a pragmatic research perspective. The research method that was employed in the research was the mixed method study which the data used for this research was containing both quantitative and qualitative data for the sake of answering the research questions. The method has a distributed ability to collaborate the collection, analysis, and integration of quantitative and qualitative data for single case studies. The aim of the research was to identifying best approach techniques during customer engagement which can enable the tele-sale representative to successfully activate the client to use the optic-fibre installed, and identifying the key components during the customer engagement that can be improved to reduce their impact on reducing the chances of a successful activation. It was concluded that providing quality services to customers can be established by developing a customer service model. It was further concluded that there is a need for the tele-sale representative to be knowledgeable with the optic-fibre. It is recommended that the same research methodology can be applied to different sectors like insurance companies and retail sector to identify whether the method will produce good results. , M.Phil. (Engineering Management)
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Design and optimisation of a linear cavity erbium-doped fibre laser for fibre-optic communication systems

  • Authors: Sigonya, Asavela
  • Date: 2020
  • Subjects: Optical fiber communication , Fiber optics , Optical amplifiers
  • Language: English
  • Type: Masters (Thesis)
  • Identifier: http://hdl.handle.net/10210/480488 , uj:43499
  • Description: Abstract: The demand for high-quality optical sources to improve the performance of high-speed fibre-optic communication systems has inevitably led to a rapid increase in the design complexity of optical sources designed for telecommunication applications. The main objective of the study was to evaluate the possibility of designing a low complexity single-frequency fibre laser operating within the C-band fibre-optic communication frequency band. An erbium-doped fibre laser was designed in this project, because of its emission spectra which cover the C-band. The relevance of the study was associated with the proposed low complexity design and the method used to optimize the optical output power quality of the designed erbium-doped fibre laser... , M.Phil. (Electrical and Electronic Engineering Sciences)
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