For higher data rate and attractive price level internet service Very High Data rate Subscriber Line 2 (VDSL2) is a perfect option. VDSL2 is a great achievement in Digital Subscriber Line (DSL) technology. It has a good impact in modern triple play (Voice, Data and Video) Internet service but for modern world applications required more data rate than the VDSL2 system can provide but it should be inexpensive and easy to install. So the desired goal of this thesis work is to achieve higher bitrates for VDSL2 system, by transmitting multiple VDSL2 signal using Plastic Optical Fiber (POF) channel instead of copper channel. POF channel is a suitable solution for high data rate application. Moreover POF is very rugged and suitable for high data rate application because of optical based transmission and it’s also very easy to implement into the interior networking. Moreover POF doesn’t have any impact of Electro Magnetic Interference because of optical transmission. So several VDSL2 signals are amplitude modulated to allocate specific frequency band and combined together which can be called as frequency division multiplexing and POF is used as channel to carry the combined signal which provide much higher bit rate than single signal and efficiently utilize the bandwidth of the channel. Then at the receiver end the combined signals are split and amplitude demodulate at the respective receiver to recover the expected frequency band for the receiver.

This thesis researches in the structure and fabrication of lensed fibers. To begin with, a novel method for automating fiber endface polishing to form quadrangular-pyramid-shaped fiber endface (QPSFE)-like shape is presented. This system successfully supported automatic polishing with an encouraged fiber tip offset. Such an automatic polishing system can also be applied to any other type of fiber endface. Next, an advanced polishing method to form an elliptical microlens endface from a QPSFE-like shape fiber is proposed. There are many advantages of this approach. First, the process to remove the tip of the fiber can be omitted and be replaced by the proposed process. This would raise the yield of the manufacturing of the lensed fiber and reducing manufacturing time and eliminating the possibility of human error. Second, after the process of the proposed method, an elliptic microlens is formed on the end of fiber and the fusing step can be skipped. In addition, in optical module packaging, laser welding used to attach components is expected to cause relative motion between the pre-aligned components. Such shifts might considerably reduce the efficiency of light coupling. This thesis provides a particular method to measurement the fiber shifts along the three axes quickly and precisely. Furthermore, the efficient coupling of plastic optical fibers (POFs) to the light source has become critical. Two kinds of new schemes of lensed optical fiber for POFs are proposed. The first type of lensed plastic optical fiber (LPOF) scheme is fabricating a convexo-concave-shaped fiber endface (CCSFE) by joining a flat-end POF and a convexo-concave plastic lens (CCPL). The second type of LPOF scheme is fabricating a hyperbola shape LPOF by using electrical force. Both designs of the LPOF all have advantages of easy fabrication and automatic manufacture.

Approximately 1% of women will experience menopause before the age of 40, a condition known as premature ovarian failure (POF). The goal of this thesis was to identify genetic causes of POF by examining a number of candidate factors in POF patients and control women. Carriers of FMR1 premutations (55-200 CGG repeats) are known to be at increased risk of POF. A higher prevalence of alleles between 35-54 repeats was found among POF patients (p=0.01), suggesting that risk for POF may extend outside the classic premutation range. There was no evidence for any difference in FMRI promoter methylation or gene expression between cases and controls. Allele distributions of gene polymorphisms in the androgen receptor (AR), estrogen receptor (ß, sex hormone binding globulin, and FSH receptor genes did not differ between POF patients and controls. However, haplotype at the estrogen receptor a gene, ESRI, was found to be associated with POF in a simple dominant manner (RR=9.7; 95% CI=2.6-35.6). Although the functional effect of this haplotype could not be confirmed, it may confer a more active promoter that influences risk by increasing the rate of follicular atresia. X-chromosome inactivation (XCI) skewing can indicate an abnormal X chromosome and may therefore be increased in POF patients. There was no increase in skewed XCI >90% in patients with secondary amenorrhea, however, there was a significant increase in 4 POF patients with primary amenorrhea (p=0.001). No X-chromosome abnormalities were detectable by high resolution DNA microarray, and skewed XCI may be explained by a trisomic rescue event causing reduced follicular pool. Age-related chromosome factors were assessed to determine if POF patients demonstrate an increased rate of cellular aging. With age, XCI skewing and AR methylation increase and telomere length decreases. There was no difference in skewing or methylation between patients and controls. Surprisingly telomere length was increased in POF patients (p=0.04), a finding that may be explained by abnormal estrogen exposure. Genotype at the longevity-associated APOE gene was not associated with POF. In conclusion, these findings have illuminated several new areas of research in this field and provide background for future research into POF pathogenesis.

This dissertation explores a few techniques to realize a low-cost monolithic fiber-optic receiver with large-area photo detectors in advanced CMOS processes that could potentially support multi-gigabit digital data across 10 to 20 meters plastic optical fibers (POF). The first techniques investigated in this dissertation are the use of an external pseudo-differential photo detector chip to reduce the impact of the inductive parasitics, and the use of a cross-coupled regulated-cascode (CC-RGC) buffer to relieve the DC voltage headroom issues found in conventional regulated-cascode (RGC) buffers in technologies with low power supply voltages. The second technique investigated in this thesis is the super-Gm transimpedance amplifier (SGM-TIA) that can be used to produce a very small input impedance in order to drive a very large parasitic capacitance exhibited by an integrated photo detector in advanced CMOS processes. The third technique investigated is a linear equalizer with multiple shunt-shunt feedbacks that can be utilized to produce a slowly-rising peaking response in order to compensate for the frequency-dependent losses exhibited by the integrated NW/P-sub photo detector. Two prototype POF receiver test chips have been implemented in TSMC’s 65 nm CMOS processes and non-return-to-zero optical data transmissions have been demonstrated at data rates up to 3.125 Gbps and 4.25 Gbps, respectively, with a 2.5 Gbps grade 670 nm vertical-cavity surface-emitting laser based electro-optical transmitter.

This dissertation explores a few techniques to realize a low-cost monolithic fiber-optic receiver with large-area photo detectors in advanced CMOS processes that could potentially support multi-gigabit digital data across 10 to 20 meters plastic optical fibers (POF). The first techniques investigated in this dissertation are the use of an external pseudo-differential photo detector chip to reduce the impact of the inductive parasitics, and the use of a cross-coupled regulated-cascode (CC-RGC) buffer to relieve the DC voltage headroom issues found in conventional regulated-cascode (RGC) buffers in technologies with low power supply voltages. The second technique investigated in this thesis is the super-Gm transimpedance amplifier (SGM-TIA) that can be used to produce a very small input impedance in order to drive a very large parasitic capacitance exhibited by an integrated photo detector in advanced CMOS processes. The third technique investigated is a linear equalizer with multiple shunt-shunt feedbacks that can be utilized to produce a slowly-rising peaking response in order to compensate for the frequency-dependent losses exhibited by the integrated NW/P-sub photo detector. Two prototype POF receiver test chips have been implemented in TSMC’s 65 nm CMOS processes and non-return-to-zero optical data transmissions have been demonstrated at data rates up to 3.125 Gbps and 4.25 Gbps, respectively, with a 2.5 Gbps grade 670 nm vertical-cavity surface-emitting laser based electro-optical transmitter.

Approximately 1% of women will experience menopause before the age of 40, a condition known as premature ovarian failure (POF). The goal of this thesis was to identify genetic causes of POF by examining a number of candidate factors in POF patients and control women. Carriers of FMR1 premutations (55-200 CGG repeats) are known to be at increased risk of POF. A higher prevalence of alleles between 35-54 repeats was found among POF patients (p=0.01), suggesting that risk for POF may extend outside the classic premutation range. There was no evidence for any difference in FMRI promoter methylation or gene expression between cases and controls. Allele distributions of gene polymorphisms in the androgen receptor (AR), estrogen receptor (ß, sex hormone binding globulin, and FSH receptor genes did not differ between POF patients and controls. However, haplotype at the estrogen receptor a gene, ESRI, was found to be associated with POF in a simple dominant manner (RR=9.7; 95% CI=2.6-35.6). Although the functional effect of this haplotype could not be confirmed, it may confer a more active promoter that influences risk by increasing the rate of follicular atresia. X-chromosome inactivation (XCI) skewing can indicate an abnormal X chromosome and may therefore be increased in POF patients. There was no increase in skewed XCI >90% in patients with secondary amenorrhea, however, there was a significant increase in 4 POF patients with primary amenorrhea (p=0.001). No X-chromosome abnormalities were detectable by high resolution DNA microarray, and skewed XCI may be explained by a trisomic rescue event causing reduced follicular pool. Age-related chromosome factors were assessed to determine if POF patients demonstrate an increased rate of cellular aging. With age, XCI skewing and AR methylation increase and telomere length decreases. There was no difference in skewing or methylation between patients and controls. Surprisingly telomere length was increased in POF patients (p=0.04), a finding that may be explained by abnormal estrogen exposure. Genotype at the longevity-associated APOE gene was not associated with POF. In conclusion, these findings have illuminated several new areas of research in this field and provide background for future research into POF pathogenesis.

Approximately 1% of women will experience menopause before the age of 40, a condition known as premature ovarian failure (POF). The goal of this thesis was to identify genetic causes of POF by examining a number of candidate factors in POF patients and control women. Carriers of FMR1 premutations (55-200 CGG repeats) are known to be at increased risk of POF. A higher prevalence of alleles between 35-54 repeats was found among POF patients (p=0.01), suggesting that risk for POF may extend outside the classic premutation range. There was no evidence for any difference in FMRI promoter methylation or gene expression between cases and controls. Allele distributions of gene polymorphisms in the androgen receptor (AR), estrogen receptor (ß, sex hormone binding globulin, and FSH receptor genes did not differ between POF patients and controls. However, haplotype at the estrogen receptor a gene, ESRI, was found to be associated with POF in a simple dominant manner (RR=9.7; 95% CI=2.6-35.6). Although the functional effect of this haplotype could not be confirmed, it may confer a more active promoter that influences risk by increasing the rate of follicular atresia. X-chromosome inactivation (XCI) skewing can indicate an abnormal X chromosome and may therefore be increased in POF patients. There was no increase in skewed XCI >90% in patients with secondary amenorrhea, however, there was a significant increase in 4 POF patients with primary amenorrhea (p=0.001). No X-chromosome abnormalities were detectable by high resolution DNA microarray, and skewed XCI may be explained by a trisomic rescue event causing reduced follicular pool. Age-related chromosome factors were assessed to determine if POF patients demonstrate an increased rate of cellular aging. With age, XCI skewing and AR methylation increase and telomere length decreases. There was no difference in skewing or methylation between patients and controls. Surprisingly telomere length was increased in POF patients (p=0.04), a finding that may be explained by abnormal estrogen exposure. Genotype at the longevity-associated APOE gene was not associated with POF. In conclusion, these findings have illuminated several new areas of research in this field and provide background for future research into POF pathogenesis. / Medicine, Faculty of / Medical Genetics, Department of / Graduate

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Optische Polymerfasern stellen ein relativ neues Medium zur Hochgeschwindigkeitsdatenübertragung mittels moduliertem Licht dar. Sie gestatten die Verbreitung großer Datenmengen über Entfernungen bis zu ca. 100 m, ohne eine Beeinflussung durch externe elektromagnetischen Feldern. Jedoch reagieren die Fasern und somit auch ihre optischen Eigenschaften aufgrund des organischchemischen Faseraufbaus empfindlich auf das Klima ihrer Umgebung. Die Ursachen für die Abnahme der optischen Transmission aufgrund von klimatischen Einflüssen (Alterung, Degradation) werden mittels chemisch analytischer Verfahren wie Chemilumineszenz (CL) und Fourier Transform Infrarot (FTIR) Spektroskopie untersucht. Dabei kommen fünf, von verschiedenen Herstellern bezogene, Multimode- POFs aus PMMA in sieben verschiedenen Klimaten zum Einsatz. Drei dieser fünf POFs werden genauer untersucht, um den Einfluss einzelner Parameter festzustellen und optische Langzeitstabilität aufgrund von Kurzzeittests vorherzusagen. Als erstes erfolgt eine Kennzeichnung unbeanspruchter POF Komponenten (Kern, Mantel und nackte POF als Kombination von Kern und Mantel) über ihre physikalischen und chemischen Eigenschaften. Die Glas- und die Schmelztemperaturen liegen im Bereich von 120 °C bis 140 °C, das Molekulargewicht des Kerns bei größenordnungsmäßig 105 g mol-1 ;. FTIR-Messungen zeigen zwar Unterschiede in der chemischen Zusammensetzung der Mäntel aber keine Unterschiede bei den Kernen. Bei zwei der POF Proben / die als Kabel (Kern, Mantel und Schutzhülle) für 3300 Stunden einem Klima aus 92 °C und 95 % relativer Feuchte (r.F.) ausgesetzt waren, verringern sich daraufhin die optische Transmissionen in unterschiedlicher Weise. Die Untersuchung der zugehörigen nackten POFs mittels CL, FTIR, Thermogravimetrie (TG), UV/VIS und Gel Permeation Chromatographie (GPC) lässt eine stärkere Schädigung der Mäntel als der Kerne vermuten. Wahrscheinlich führt eine starke Manteldegradation zu einer erhöhten Absorption und Fehlstellen im Mantel und damit zu einer Transmissionsabnahme. Daher scheint die optische Stabilität der POF stärker durch die thermo-oxidative Stabilität des Mantels bestimmt zu sein als durch die des Kernes. Drei nackte POFs (Kern und Mantel) sind unterschiedlich lang (30 Stunden bis 3000 Stunden) folgenden Klimaten ausgesetzt: 92 °C / 95 % r.F., 92 °C / 50 % r.F., 50 °C / 95 % r.F., 90 °C / geringe Feuchte, 100 °C / geringe Feuchte, 110 °C / geringe Feuchte and 120 °C / geringe Feuchte. Auch in diesen Klimaten ergaben sich probenbedingte unterschiedliche Transmissionsänderungen. Die Ergebnisse deuten stark darauf hin, dass bei gleichzeitig hoher Temperatur und hoher Feuchte physikalische Änderungen wie die Volumenausdehnung die Hauptursachen für die Abnahme der optischen Transmission bilden. Ein weiterer Einflussfaktor ist die chemische Zusammensetzung der Mäntel. Bei Kombination von hoher Temperatur und geringer Feuchte erzeugen in den Anfangsstadien der Alterung physikalische Änderungen Transmissionsabnahmen, vermutlich entstehen Fehlstellen in der Kern-Mantel-Grenzschicht. Hinzukommen in den späteren Stadien wahrscheinlich zunehmende Lichtabsorption in Kern und Mantel. L. Jankowski (Doktorand in der BAM) bestätigt diese Annahme durch parallel ausgeführte optische Simulationsrechnungen. Auch für nackte POFs scheint also die thermo-oxidative Stabilität die optische Stabilität zu bestimmen. Kurzzeitalterungstests sollen Aufschluss über den Einfluss individueller Klimaparameter auf die POF Eigenschaften geben. Es zeigt sich bei dauerhaft hoher Temperatur und variabler Feuchte aufgrund des physikalisch absorbierten Wassers bis zu einem gewissen Grad ein reversibles Verhalten des Transmissionsverlustes. Dieses Verhalten tritt aber nur kaum merkbar auf, wenn bei konstanter hoher Feuchte die Temperatur variiert wird. Bei Raumtemperatur und variabler Feuchte stellt sich jedoch ein voll reversibles Verhalten des Transmissionsverlustes ein. Die hier beschriebenen Untersuchungen sind als Ausgangspunkt für weitergehende Forschungen zu verstehen. Die begrenzte Zurverfügungstellung von POF Basisdaten durch die Hersteller und der zeitaufwendige klimabedingte Alterungsprozess beschränken die Ergebnisse mehr oder weniger auf die untersuchten Proben. Signifikante allgemeine Aussagen erfordern aber beispielsweise zusätzliche statistische Daten der Produktionsschwankungen von POF Eigenschaften. Dennoch besitzen die hier beschriebenen Tests das Potential für eine Annäherung an die optische Langzeitstabilität und deren Vorhersage. / Polymer optical fibers (POFs) are a rather new tool for high-speed data transfer by modulated light. They allow the transport of high amounts of data over distances up to about 100 m without be influenced by external electromagnetic fields. Due to organic chemical nature of POFs, they are sensitive to the climate of their environment and therefore the optical fiber properties are as well. Hence, the optical stability is a key issue for long-term applications of POFs. The causes for a loss of optical transmission due to climatic exposures (aging/degradation) are researched by means of chemical analytical tools such as chemiluminescence (CL) and Fourier transform infrared (FTIR) spectroscopy for five different (with respect to manufacturers) step-index multimode PMMA based POFs and for seven different climatic conditions. Three of the five POF samples are studied more in detail to realize the effects of individual parameters and for forecasting longterm optical stability by short-term exposure tests. At first, the unexposed POF components (core, cladding, and bare POF as combination of core and cladding) are characterized with respect to important physical and chemical properties. The glass transition temperature Tg, and the melting temperature Tm are in the region of 120 °C to 140 °C, the molecular weight (Mw) of cores is in the order of 105 g mol-1. POFs are found to have different chemical compositions of their claddings as could be detected by FTIR, but identical compositions of their cores. Two of the POFs are exposed as cables (core, cladding and jacket) for about 3300 hours to the climate 92 °C / 95 % relative humidity (RH) resulting in a different transmission decrease. Investigating the related unexposed and exposed bare POFs for degradation using CL, FTIR, thermogravimetry (TG), UV/visible transmittance and gel permeation chromatography (GPC) suggest that claddings of POFs are more affected than cores. Probably the observed loss of transmission is mainly due to increased light absorption and imperfections at the core-cladding boundary caused by a large degradation of claddings. Hence, it is highly possible that the optical transmission stability of POFs is governed mainly by the thermo-oxidative stability of the cladding and minor of the core. Three bare POFs (core and cladding only) are exposed for different duration of exposure time (30 hours to 4500 hours) to 92 °C / 95 %RH, 92 °C / 50 %RH, 50 °C / 95 %RH, 90 °C / low humidity, 100 °C / low humidity, 110 °C / low humidity and 120 °C / low humidity. In these climates their transmission variations are found to be different from each other, too. The outcomes strongly inform that under high temperature and high humid climates physical changes such as volume expansion, are the main sources for the loss of optical transmission. Also, the optical transmission stability of POFs is found to be dependent on chemical compositions of claddings. Under high temperature and low humid conditions, a loss of transmission at the early stages of the exposure is mainly caused by physical changes, presumable by corecladding interface imperfections. For the later stages of exposures it is proposed to an additional increase of light absorption by core and cladding owes to degradation. Optical simulation results obtained parallel by Mr. L. Jankowski (a PhD student of BAM) are found to confirm these results. For bare POFs, too, the optical stability of POFs seems to depend on their thermo-oxidative stability. Some short-term exposure tests are conducted to realize influences of individual climatic parameters on the transmission property of POFs. It is found that at stationary high temperature and variable humidity conditions POFs display to a certain amount a reversible transmission loss due to physically absorbed water. But in the case of varying temperature and constant high humidity such reversibility is hardly noticeable. However, at room temperature and varying humidity, POFs display fully reversible transmission loss. The whole research described above has to be regarded as a starting point for further investigations. The restricted distribution of fundamental POF data by the manufacturers and the time consuming aging by climatic exposures restrict the results more or less to the samples, investigated here. Significant general statements require for example additional information concerning the variation of POF properties due to production. Nevertheless the tests, described here, have the capability for approximating and forecasting the long-term optical transmission stability of POFs.<br> --------------<br> <i>Auch im Druck erschienen:</i><br> Appajaiah, Anilkumar: Climatic stability of polymer optical fibers (POF) / Anilkumar Appajaiah. - Bremerhaven : Wirtschaftsverl. NW, Verl. für neue Wiss., 2005. - Getr. Zählung [ca. 175 S.]. : Ill., graph. Darst. - (BAM-Dissertationsreihe ; 9)<br> ISBN 3-86509-302-7

No description available.