For high-speed laser modules in lightwave communication systems, the butterfly laser modules are widely used. When laser welding is applied to assemble a butterfly package, it is usually necessary to have mechanical elements such as substrates, fiber ferrule, and clips of house materials to facilitate fiber handing and retention within the package. One of the greatest challenges for packaging these optoelectronic components by employing laser welding is to pursue the reliable and accurate joint. However, during the welding process, rapid solidification of the welded region and the associated material shrinkage often cause a post-weld-shift (PWS) of fiber. The PWS can never be completely eliminated in the laser welding process, and significantly affects the package yield. The PWS induced fiber alignment shifts of fiber ferrule-clip (FFC) joints in high-speed butterfly laser packaging by laser welding technique has been studied experimentally. There are two types of clip design in the FFC joint: the type I design is without a gap between clip and fiber ferrule and type II is a 5

Background: Speech rate plays an essential role in overall speech intelligibility in fluent speakers and is an important variable affecting fluency in people who stutter (PWS). There are no normative speech rate data for South African English (SAE). In PWS, attempts to manipulate speech rate for improved fluency have mostly focused on articulation rate. Revisiting the role of pauses in speech rate and the manipulation of both frequency and duration of pauses was deemed necessary to investigate a potentially valuable alternative strategy to assist PWS in rate reduction and possible improved fluency. Aims: The aims of this study were to investigate the speech rate and pause use for first language (L1) and second language (L2) SAE fluent speakers and PWS in both monologue and reading tasks. In addition, this study investigated if the manipulation of pause use could increase fluency in L1 and L2 PWS given six sessions of pause instruction in SAE. Methods: 80 fluent speakers (40 L1 SAE and 40 L1 isiZulu) and 14 PWS (7 L1 SAE and 7 L1 isiZulu) were asked to engage in a 2-minute monologue and a reading task in order to calculate the mean speech rate, frequency of pauses and average pause duration for each group. Following baseline measures, the 14 PWS were randomly assigned to either immediate or delayed intervention consisting of 6 sessions addressing manipulation of pauses. A crossover treatment design allowed for repeated measures of speech rate and pause use across three data collection periods. Results: Results revealed L1 and L2 SAE fluent speakers differed significantly in speech rate and frequency of pauses in reading and in pause length in the monologue. L1 and L2 PWS differed in frequency of pauses in reading. L1 fluent speakers and PWS differed in speech rate and both measures of pause use in reading. L2 fluent speakers and PWS differed in frequency of pauses in the monologue. Results from the crossover intervention for the PWS revealed a significant decrease in percentage syllables stuttered (% SS) for the delayed treatment group and a clinically significant decrease in % SS for both groups, in conjunction with a reduced speech rate that could be linked to increased frequency and/or average duration of pauses. Conclusions: This study presented speech rate and pause use norms for both fluent speakers and PWS, L1 and L2 SAE speakers that may provide useful guidelines for speech language pathologists in South Africa. Additionally, the intervention results for PWS presented efficacy data for six sessions of pause manipulation with measurable findings for improved fluency.

Abstract In this thesis, we have studied the post-weld-shift (PWS) in laser welding technique for laser module packaging. The joining method for packaging of laser module by laser welding technique can offer a number of significant advantages. It provides strong joint strength, therefore, the packaging has good long-term stability. It also provides high-speed and high-volume production, and hence the packaging is potential low cost. However, the laser welding process has caused PWS of laser module, would decay the coupling efficiency of laser module. We investigate the weld-spot by using metallographic method. The PWS in stainless steel (SS304L) plate is studied experimentally and numerically. The metallographic results are in good agreement with the Finite-Element-Method (FEM) results that the PWS in x-y plane can be neglected. Based on the experimentally and numerically results of PWS in SS304L, we investigate the yield improvement of laser module packaging. The laser hammer technique was used to improve the coupling efficiency of laser module. The results show displacement of the z-axis is from 1 to 9 (£gm) that equals to the angle changes of upper parts of laser module from 0.38¡Ñ10-2 to 3.4¡Ñ10-2 (degree). Therefore, the coupling efficiency of laser module can be improved from 4 to 20 (%).

The fiber clips is a device for holding an optical fiber which is enclosed in the ferrule, adjustment it to the optimum aligning position with respect to the laser diode and fixing it on the substrate of the butterfly-type laser module by the laser welding. It is hard for the extant saddle shaped clips to be manufactured and the result causes the unable mass production and the high cost. Otherwise, the packaging process has caused PWS of laser module, would decay the coupling efficiency of laser module. Aim at the shortcomings, the purpose of this study proceeds to the creative design of the fiber clips with the systematic engineering design and make a set of the manufacturing method by the pressing die to cause automatic mass production in the future. First, identify the basic characteristics based on an analysis of the patents and then get the conditions and trend. Second, find the function needs and elaborate the specification of design. Third, the use of morphological analysis method and design process is formulated to synthesize and evaluate the improving structure. Finally, taking the design cases will develop the embodiment design and prove the propose approach for the design process. Otherwise, it develops an improvement technique and adjustment method for PWS and wishes can reduce or improve the effects of it.

The objective of this study is to investigate the technique of the PWS (Post-Weld-Shift) measurement in cylindrical-type laser diode module packaging processes. Including measure the shift in focus plane and the run-out between the axis of laser diode and optical fiber. The objective of this technique is to quantify the PWS in packaging processes. This technique can improve the efficient of the laser hammering technique. The measurement technique developed in this study employs a laser displacement meter (Keyence LC-2430) to measure the profile and position the upper housing of laser diode module. Using the concepts of ellipse and symmetric figure, the Ellipse Fitting Method (EFM) and the Symmetric Center Method (SCM) are developed. A simulation program is coded for discussing the relationship between the measurement error and the roundness of the optical fiber housing. Finally, these measuring technique are applied on the laser diode module packaging system (Newport-LW4000) to measure the PWS. The experimental measuring data of PWS is 3.5£gm, which is reasonable in compare to the estimate alignment offset (2.9£gm to 5.9£gm) by the coupling efficiency method. Therefore it is believed that the technique developed in this study is feasible and practical.

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Optical scattering techniques are suitable probes for studying weak disordered refractive index media such as biological cells and tissues. Several brain diseases accompany the nano-to-submicron scales’ structural alterations of the basic building blocks of cells/tissues in the brain and skin fibroblasts. For example, several molecular modifications such as DNA methylation, and histone degradation occur in cells earlier than morphological changes detectable at a microscopic level. These alterations also change the refractive index structures of the cells/tissues at the nano-to-submicron scales. Unfortunately, traditional methods do not allow the detection of these alterations in the early stages of diseases. Recent developments in mesoscopic optical physics-based techniques can probe these alterations. Particularly, mesoscopic light transport and localization approaches enable the measurements and quantifications of the degree of structural alterations in the cells/tissues and unprecedented information on progressive brain diseases. This dissertation provides a detailed study of the structural changes at nano-to-submicron levels in human brain cells/tissues and human skin fibroblasts in two major neurodegenerative diseases, Alzheimer’s disease (AD) and Parkinson's disease (PD), using dual spectroscopic imaging techniques, namely partial wave spectroscopy (PWS) for light transport and inverse participation ratio (IPR) for weak light localization. In particular, a nanoscale-sensitive advanced PWS technique is used to quantify the structural alterations in cells/tissues. Further, the IPR technique is used to quantify molecular-specific mass density alterations within cells using their light localization properties via confocal imaging. These dual optical scattering techniques were utilized to measure the degree of structural disorders, termed ‘disorder strength’, by distinguishing the diseased cells/tissues from normal ones in the human brain and human skin fibroblasts due to neurodegenerative diseases. Our results show that the degree of structural disorder (����) increases in the affected cells and tissues relative to the normal, both at the cellular/tissue level and in the DNA molecular mass density structural levels. The results of the studies strongly reveal that the degree of structural disorder strength (����) is an effective biomarker/numerical indicator for brain disease diagnostics.