The telecom industry is today categorized by being able to wirelessly transmit large amounts of data between systems in a short time. A precondition for this is that the PCBs (printed circuit board) being developed and manufactured can handle and distribute large amounts of data internally. Often presented as multiple high-speed links up to 10-28 Gbit/s. The PCBs of today contains electric conductors, which all lead from one point to another, with no possibility of branching or flexibility without being rebuilt. A significant problem with all these electric conductors in the PCBs and all the PCBs close contact with each other is the interference building up between them. EMI is a general explanation for this, Electro Magnetic Interference. To avoid this problem and instead meet the constraints of EMC, Electro Magnetic Compatibility, these electric conductors can be replaced with optical conductors. This new concept with optical conductors is not initially going to replace all electric conductors but replace most of the existing high speed links and the traditional point to point communication with optical high speed multidrop. Not just fulfilling the need of EMC, these conductors are also able send one single signal to several different receivers. The optical conduction is happening inside a plate of PC-plastic, allowing the signal to travel throughout the whole PCB if needed. While this is happening, all receivers in need of data can pick up the sent-out signal. / Telekombranschen karaktäriseras av att stora mängder data för över trådlöst mellan system på kort tid. En förutsättning för detta är också att de kretskort som utvecklas och tillverkas måste kunna hantera och distribuera stora mängder data internt på kortet. Detta sker ofta i multipla höghastighetslänkar på upp till 10–28 Gbit/s. Dagens kretskort bygger på elektriska ledare, som har en början och ett slut. Det vill säga ingen möjlighet till förgrening eller förändring utan ombyggnad. Ett problem med alla dessa ledare i kretskorten och kretskortens nära kontakt med varandra är att interferens sker mellan dem. EMI är en känd beteckning för detta, Elektromagnetisk interferens. För att undgå detta problem och istället uppfylla EMC, Elektromagnetisk kompatibilitet, kan dessa elektriska ledare ersättas med optiska. Detta nya koncept med optiska ledare ska till en början inte ersätta alla elektriska ledare utan målet är att ersätta merparten av de på korten befintliga höghastighetslänkar och att ersätta de traditionella höghastighetslänkarnas point to point med en optisk multidroplösning. Utöver att dessa ledare uppfyller EMC så bidrar de även till att en signal kan skickas från samma sändare till flera olika mottagare. Då den optiska ledningen sker genom en skiva i PC-plast har signalen inget förbestämt mål, utan alla mottagare i behov kan plocka upp signalen.

An experimental and a theoretical analysis for a laser beam propagating through multiple phase screens was performed. The theoretical analysis showed that the statistics for the intensity fluctuations, which can be predicted by the HK and the I-K distributions, could be derived from a multiplicative process using statistical distributions derived from Gaussian statistics. For the single phase screen experiment, the experimental normalized moments were compared with the normalized moments of both the HK and I-K distributions . In addition, the intensity data was lowpass filtered to yield moments that are predicted by the gamma distribution. The single phase screen data was segmented into small time intervals, and all time segments with approximately the same variance were grouped together into bins to yield normalized moments for each bin that are predicted by the Rician distribution. Also, the normalized moments for two and three phase screen experiments were measured. Finally, a computer program was written to simulate K distributed noise from two independent Gaussian noise sources.

Processing and analysis routines giving normalized moments of optical intensity, structure functions of wind velocity and temperature, central moments, and various measures of the turbulence parameter, C2N, are presented. Rapid analog-to-digital data conversion and storage to implement this analysis using MINC 11/23 with RT11 operating system are discussed. Coding for file organization and implementation of processing routines on the VAX 11/750, VMS operating system are also discussed.

This dissertation expounds growing insight of the electrospray droplet ionization mechanism following ablation of dried hydrophobic and hydrophilic molecules using femtosecond laser pulses and mass analysis of the gas phase ions. Both hydrophobic and hydrophilic molecules were laser vaporized into an electrospray solvent opposite in polarity revealing appreciable ion intensity for all samples in contrast to ESI-MS and DESI measurements were solubility of the analyte in the spray solvent is a prerequisite. Quantitative analysis of equimolar protein solutions was established using LEMS reporting over three decades of quantitave response with little evidence of ion suppression. In contrast, ESI-MS measurements of similar equimolar protein solutions revealed severe ion suppression eliminating ion current from one of the protein analytes. Finally, the nature of an analyte following nonresonant laser vaporization has been the subject of debate. Aqueous trypsin was laser vaporized into an electrospray solvent containing either buffer or acid with substrate. LEMS measurements using buffer revealed enzyme-substrate intermediate charge states and continued enzymatic activity while the lack of enzyme-substrate intermediates and stymied enzymatic activity observed using acid suggests nonresonant laser vaporization preserves solution phase structure. This dissertation also extends considerably the use of LEMS for identification and characterization of energetic materials in their pre- and post-blast forms without sample preparation. The use of mulivarate analysis for the classification of large sample sets was also demonstrated showing high fidelity assignment of commercial formulations to their manufacturer. Five unburnt smokeless powders investigated using LEMS revealed unique combinations of organic molecules such as stabilizers and plasticizers using a simple electrospray solvent. Principal component analysis (PCA) provided exact classification of the mass spectra with respect to the manufacturer of the ordinance. LEMS measurements were then obtained from five commercial gunshot residue samples, or post-blast smokeless powder, revealing trace amounts of organics such as the stabilizers and large quantities of inorganic barium originating from the primer. Principal component analysis (PCA) again provided exact classification of the gunshot residue mass spectra with respect to the manufacturer of the ordinance. The use of a common transition metal complexation agent enabled full characterization of eight gunshot residue samples to include the heavy metals contained in the primer and the organics such as the stabilizers and plasticizers without any sample preparation or pre-concentration procedures. Principal component analysis (PCA) again provided high fidelity classification of the gunshot residue mass spectra with respect to the manufacturer of the ordinance after mass analysis with LEMS. Finally, highly energetic formulations such as composition 4 (C-4) and detonation cord subjected to nonresonant femtosecond laser vaporization enabled full characterization of these complex compositions identifying binders, stabilizers, the explosive ingredient and age-related decomposition derivative signature molecules with appreciable ion current detected using both positive and negative ion modes. / Chemistry

The effects of tension and compression applied to unbonded InGaAsP semiconductor diode lasers have been studied. A theoretical calculation of the stress distribution within the laser and an analysis of the effect of strain on optical gain in semiconductors is presented. The observed dependence of threshold, wavelength, and polarization of the laser output on the applied stress is explained in terms of the strain dependence of the valence-band wavefunctions. The polarization behaviour is found to be related to thermal stress and the structure of the device. A technique has been developed to measure the thermal stress induced by current heating at the 105 dynes/cm2 level. The effect of stress on the below threshold behaviour of the lasers was investigated. The results are consistent with the strain dependence of the TE and TM mode gains. / Thesis / Master of Engineering (ME)

This thesis documents a study of bonding stress and the reliability of GaAs-based lasers for high-power applications. GaAs-based lasers were bonded to oxygen-free high- conductivity (OFHC) copper heat sinks using a eutectic PbSn solder or a silver-filled conductive epoxy, and life tested. Epoxy-bonded devices were observed to have a larger failure rate on life test than solder-bonded devices. Bonding stress, as measured by the degree of polarization (DOP) of photoluminescence, was found to be the largest in epoxy-bonded devices. As well, the type of heat sink and bonding adhesive affected the stress in the laser material, with bonding stress increasing when there was a larger mismatch of coefficients of thermal expansion between the laser material, adhesive and heat sink. The reliability of the lasers was affected by the amount of force applied to unbonded laser chips. As the applied force increased on a chip centred on a groove, the rate of degradation in the output power increased. A limit in stress tolerance was observed in the lasers, which meant that larger amounts of stress would lead to increased rates of degradation in the output power. As well, the performance of lasers selected from a batch showing poor reliability degraded at an accelerated rate after several hours of operation under applied strain. / Thesis / Master of Engineering (ME)

The detection of trace amounts of H and D present in Zr-2.5%Nb in the form of ZrH and ZrD, respectively, by LIBS was explored. The intended use case for this experimentation was CANada Deuterium Uranium (CANDU) nuclear reactor pressure tube inspections where hydride buildup can lessen the mechanical strength of these components. As these tubes carry coolant and house the fuel bundles, their integrity is paramount. A LIBS inspection method is of interest in the nuclear industry due to the operational flexibility it would introduce and its ability to reduce the cost, time, and radiation dose associated with inspection campaigns of pressure tubes in CANDU nuclear reactors. Using LIBS, simultaneous detection of H and D was achieved in a low-pressure air environment using a microjoule, picosecond pulsed laser and emission being captured by a high-resolution spectrometer. The emission lines of the two species were blended, however, two peaks can be seen. Experiments using a milijoule, nanosecond pulsed laser in a LIBS setup were also conducted at atmospheric pressures. These experiments failed to show D emission, however. In addition to detecting emission from H and D, a Monte Carlo algorithm was developed for estimating the error associated with a LIBS inspection of a pressure tube segment. ZrH and ZrD form heterogeneous structures in the bulk of the Zr-2.5%Nb pressure tube material, meaning that a single measurement would not be indicative of the entire tube. Using metallographs of artificially hydrided pressure tube samples, the error within a given confidence interval was found as a function of number of measurement sites and ablation diameter. Furthermore, the impacts to Zr-2.5%Nb based on intense laser-matter interactions was investigated by optical microscopy and interferometry, allowing for 3-dimensional reconstructions of ablation craters. The morphology of millijoule, nanosecond pulsed laser-matter interaction and microjoule, picosecond pulsed laser-matter interaction were the subjects of this investigation. The salient difference between the two interactions is the evidence of substantial melting and subsequent re-deposition of material in the case of nanosecond interactions, whereas picosecond ablation yielded little melting. These results support the further development of a LIBS-based inspection method for determining the concentration of H and D in Zr-2.5%Nb. It was found that a vacuum environment allows for the simultaneous detection of H and D emission. Further experimentation should explore using low-pressure buffer gas environments as a method to further distinguish emission between the two species. / Thesis / Master of Applied Science (MASc)

A numerical model of the temperature field during pulsed laser cutting of thin sheets (approximately 2.5 x l0⁻⁵ m) was developed. Cutting was simulated through removal of nodes from a finite difference scheme based on sensible heating to the phase change temperature and a single value of latent heat (melting or vaporization). The pulsed laser model predicts a heat-affected zone of less than 0.02 mm for pulsed laser cutting. For comparable cutting with a continuous power laser, a heat-affected zone between 0.05 and 0.10 mm is predicted. Thermal stress levels were predicted to be an order of magnitude lower for pulsed laser cutting than for continuous power cutting. The stress levels predicted by the model also increased with cut speed. Experimentally, pulsed laser cutting yielded better cut quality, based on less cracking, than continuous power cutting. In addition, the cut quality deteriorated as the cutting speed was increased for the continuous power laser. Presently, application of pulsed laser cutting is limited by its low cutting speed, which is restricted by the energy density of the laser. The model predicts that increasing energy density will decrease the size of the heat-affected zone and increase the maximum cutting speed. Therefore, pulsed laser cutting at high speeds should be attainable without deterioration in cut quality. / Master of Science

More efficient semiconductor lasers will be needed in tomorrow's applications. These lasers can only be realized through the application of new device processing techniques, designed to restrict current, carrier, and/or photon flow through the lasing cavity. This work aims to evaluate a non-conventional stripe laser processing technique which has the potential for effective current and possibly carrier confinement at low cost. This technique, referred to as hydrogen passivation, involves exposing laser material to a low energy hydrogen plasma, causing hydrogen ions to bind to charged acceptor and donor atoms. Such binding compensates the electrical activity of these dopant atoms and thereby increases the resistance of the exposed material. Optical confinement can also be achieved (subsequent to hydrogenation) by using a simple wet-etching process to form a lateral waveguide. Stripe lasers fabricated via hydrogen passivation have been demonstrated previously; however, the benefits of this method have not been fully explored or characterized. Our work aims to quantify the degree of current and carrier confinement provided by this technique. The cleaved cavity method of analysis is used to extract laser parameters via direct measurement. These parameters are then compared against those obtained from more conventional stripe lasers to identify improvements that have accrued from using hydrogen passivation. / Master of Science

Laser flare can often be a major issue in particle image velocimetry (PIV) involving solid boundaries in a flow or a gas-liquid interface. The use of fluorescent light from dye-doped particles has been demonstrated in water applications, but reproducing the technique in an airflow is more difficult due to particle size constraints and safety concerns. The following thesis is formatted in a hybrid manuscript style, including a full paper presenting the applications of fluorescent Kiton Red 620 (KR620)-doped polystyrene latex microspheres in PIV. These particles used are small and monodisperse, with a mean diameter of 0.87 μm. The KR620 dye exhibits much lower toxicity than other common fluorescent dyes, and would be safe to use in large flow facilities. The first sections present a general introduction followed by a validation experiment using a standard PIV setup in a free jet. This work was the first to demonstrate PIV using fluorescent KR620-doped microspheres in an airflow, and results from the experiment were compared to similar data taken using standard PIV techniques. For the free jet results, Mie-scattered and fluorescent PIV were compared and showed average velocities within 3% of each other at the nozzle exit. Based on the PIV validation requirements used, this was deemed to be more of an indication of nozzle unsteadiness rather than an error or bias in the data. Furthermore, fluorescent PIV data obtained vector validation rates over 98%, well above the standard threshold of 95%. The journal article expands on the introductory work and analyzes testing scenarios where fluorescent PIV allows for velocity measurements much closer to a solid surface than standard, Mie-scattered PIV. The fluorescent signal from the particles is measured on average to be 320 ± 10 times weaker than the Mie scattering signal from the particles. This fluorescence-to-Mie ratio was found to be nonuniform, with the typical signal ratio for a single particle expected to fall between 120 and 870. This reduction in signal is counterbalanced by greatly enhanced contrast via optical rejection of the incident laser wavelength. Fluorescent PIV with these particles is shown to eliminate laser flare near surfaces, in one case leading to 63 times fewer spurious velocity vectors than an optimized Mie scattering implementation in a region more than 5 mm from an angled surface. In the appendix, a brief summary of an experiment to characterize the temperature sensitivity of the KR620 dye is included. This experiment concluded that the KR620 particles did not exhibit sufficient temperature sensitivity to warrant further investigation at the time. / Master of Science