A High electromagnetic shielding, light weight, low cost plastic package is developed by using a woven continuous carbon fiber (WCCF) epoxy composite. Three different weaving types of WCCF, plain¡Bbalanced twill and uni-direction structure, are fabricated for understanding the shielding property of the WCCF composites. By weaving the WCCF in a balanced twill structure with excellent conductive network, it shows that the SE can reach to about 80dB under plane-wave source measurement and about 50dB in the near-field source measurement. By comparison of cost, weight, and shielding performance for optical transceiver modules fabricated by the housings of woven continuous carbon fiber, nanoscale hollow carbon nanocapulses (HCNCs) epoxy composites and nylon and liquid crystal polymer (LCP) with carbon fiber filler composite, the WCCF composites shows lower cost, light weight, and higher electromagnetic shielding than the other types of composites.

This study proposes a low cost potentiall with non-AR coated fiber grating external cavity laser (FGECL) module to apply the metro/access network. The components inside the module include uncoated FP (Fiber-Perot) laser chip, PIN detector, substrate, and cooler. The processes of package are following: (1) to utilize the die-bonder to fix the FP laser and the PIN detector on the substrate, (2) to utilize the heating apparatus to make the cooler fixed on the butterfly housing and the substrate fixed on the cooler, (3) to utilize the 353ND paste to make the thermistor fixed on the substrate, and (4) to utilize the electrothermal heating machine to melt indium wire and then adjust the fiber lens provided with higher coupling efficiency of fiber pigtail by tweezer to couple light into the fiber inside the butterfly housing. This study achieves a FGECL module with the output power of larger than 2mW and the side-mode suppression ratio (SMSR) of more than 38dB. Finally, we measure eye diagram and bit-error-rate at 2.5Gb/s of the FGECL module to analyze the impedance matching of laser diode, current signal and the limit of the dispersion to the optical communication system. The performance of the FGECL module can meet the ITU-T G.957 standard.

For the requirements of high-speed signal transmission has been increasing. Optical communication system is the way to solve the demands. The 980-nm high-power laser modules are used for optical communication system as the power of the amplifier for long distance communication. The QPSFE is used for coupling between the high-power 980nm laser diodes and the single mode fiber. This research established an on-line inspection system to inspect the fiber endface during the polishing process which is applied on a bare fiber polishing machine. The system we developed is to detect the fiber endface for QPSFE fabrication process. In this paper, we simply use couple charge device (CCD) as a position sensor to detect the grinding situation. The system had been successfully achieved on-inspection purpose, therefore; it will be the key technique toward the automatic bare fiber polishing system.

Because the need of high speed data transmission is increasing day by day, fiber optic communication have played an important role. However, with increasing of the data transmission distance, the loss of the power is a series problem. To solve this problem, the power of the signal must be amplified in a fixed distance to keep the signal reality. In the optic amplified system, the pump laser is always a 980nm high-power laser. Because of the high aspect ratio of this laser, the quadrangular- pyramid-shaped fiber endface(QPSFE) lensed fiber is needed in order to increase the coupling efficiency. There is no standard process to fabricate QPSFE now. The experiment method is as follow. The first procedure is to polish the flat-end fiber to become the QPSFE, then melt the fiber by electric arc, the QPSFE lensed fiber is formed finally. In the polishing step, the bare fiber polishing machine is used. But, the polished quantity is unavailable during polishing, so the yield of the well-polished fibers is poor, only 20%. In this research, the force sensing mechanism mounted in the polishing machine is proposed to measure the force between the fiber and the polish disk. By mounting the mechanism, there are several advantages, such as operating conveniently, increasing the polishing speed, and making the polished quantity available during polishing. Using this force sensing mechanism to develop a polish rule will improve the yield of the well-polished fibers. The strain gauge method is used to design the force sensing mechanism. Using this mechanism and taking the force analysis of the fiber polishing will make the force information between the fiber and the polish disk available. By design the parameters of this mechanism advisably, it will reach the expected purpose in this research. A 0.5

This study combined photocatalytic technology with activated carbon adsorption to decompose gaseous pollutants. Gaseous pollutants were initially adsorbed and concentrated by activated carbon and could be further decomposed more effectively by photocatalytic technology. This study coated TiO2 on the activated carbon fiber (ACF) by a sol-gel process for conducting the adsorption and decomposition of acetone in a batch reactor. Operating parameters investigated in this study included the initial concentration of acetone (13.6 £gM and 27.2 £gM), reaction temperature (50¢J~70¢J), oxygen concentration (0.5%~20%), and water vapor (0 £gM~244.9 £gM). The incident UV light of 365 nm was irradiated by a 15-watt low-pressure mercury lamp placing above the photocatalytic batch reactor. The ACF coated with TiO2 was placed in the center of the reactor. Acetone was injected into the reactor to conduct photocatalytic tests. Reactants and products were analyzed quantitatively by a gas chromatography with electron capture detector (GC/ECD) and a flame ionization detector followed by a methaneizer (GC/FID-Methaneizer). Results from the photocatalysis tests indicated that, among the commercial TiO2 (Degussa P-25), NO3-/TiO2 and SO42-/TiO2, SO42-/TiO2 had the best photoactivity reduced acetone concentration and reaction time substantially. The end products was mainly CO2 and CO, which resulted in the mineralization ratio above 95%. Results from the operating parameter tests revealed that the increase of the initial acetone concentration enhanced the amount of acetone adsorbed on the ACF, which however did not increase the reaction rate of acetone. Although the increase of reaction temperature could reduce the amount of acetone adsorbed on the ACF, decomposition rate of acetone could be promoted, so as the yield rate and mineralization ratio of products (CO2 and CO). Increasing oxygen concentration did not influence the decomposition significantly except for oxygen concentration lower than 1%. The increase of water vapor would slightly decrease the amount of acetone adsorbed on the ACF, which did not decrease the decomposition of acetone anyway. This study revealed that the decomposition of acetone on TiO2/ACF can enhance the mass transfer of acetone substantially.

In this thesis, thermal effects on Cr4+:YAG fiber are studied through numerical modeling. Crystal fiber was used as the gain medium in amplified spontaneous emission(ASE) light source, lasers, or amplifiers. Because the absorbed pump power can not be completely turned to signal in energy transition, some of the absorbed pumping power will be converted into heat, which raises the fiber temperature. In continuous-wave regime, maximum temperature, the steady-state temperature profile, and thermal stresses in the host material under single end pump are obtained by using the commercial finite elements method software ANSYS. The pump power was propagated with exponential decay inside the fiber. Because more heat was generated at the light incident region, a maximum temperature of 397K was observed from the simulation result at the same region under single-end pump of 3W. Simultaneously, a maximum tensile stress of 39 MPa was reached at the border between YAG and Silica. Finally, temperature profiles and thermal stresses were calculated in the other conditions.

Abstract The breakthrough technology in dry fiber fabrication has opened the possibility for using fiber bandwidths all the way from 1.3 to 1.6 £gm. The fiber amplifier that is in common use can not fully cover the whole, which its range is from 1.3 to 1.6 £gm. Recently, the Cr4+-doped fiber has shown a broadband emission from 1.3 to 1.6 £gm. Therefore, it is eminently suitable for super-wideband optical source. In this study, we first propose and fabricate a Cr4+-doped fiber by employing a commercial drawing-tower method, which has good core diameter uniformity, the growth speed is up to 200 m/min, and the core diameter is less than 10 £gm. The central wavelength of the ASE spectrum is at 1310 nm, and a 3-dB bandwidth is 300 nm. The divergent angle of the Cr-doped fiber is 17 o ¡Ñ 15 o and it¡¦s also similar to a single mode fiber of 16 o ¡Ñ 16 o. Low-loss fusion splice can readily be done with the standard single mode fiber, and is beneficial when integrated with the broadband WDM couplers. Therefore, it is good for commercial production and application to light wave systems.

The goal of this study is to design a new method which can be used for manufacturing the elliptic lensed fiber. The lensed fiber is obtained by heating the fiber tip in a fusing splicer at present. Before taking the fiber into fusing splicer, there are many procedures have to be checked. Those procedures will take a lot of time and increase the rate of inaccuracy. So, this research proposes a new method to form the elliptic lensed fiber by polishing. In this study, we simply use couple charge device (CCD) to detect the shape of the fiber tip. Than, we use the detected program to get the curvature of fiber tip. The system had been successfully achieved the purpose of curvature-controlled. The research will be the key technique toward the automatic bare fiber polishing system.

ABSTRACT The spectral characteristics for non-AR coated fiber grating lasers were studied theoretically and experimentally. The lensed fiber was used to improve coupling efficiency between laser and fiber. The tapered fibers were fabricated by using the mixture of HF and oil with different density to increase etched taper angle. The coupling efficiency could reach more than 60%. A single-mode operation for a fiber grating external cavity laser (FGECL) was simulated. The results showed that the SMSR, emitted power, and wavelength drift were dependent on the related device parameters. Our calculations showed that the strong current-dependent SMSR oscillation was from the mode selection by the fiber grating external cavity and the heating effect in the Fabry-Perot (FP) laser. A 1.55mm FP laser chip that one facet was coated a high reflectivity (HR) of 90% and another facet was uncoated. In our experiment and simulation of FGECL, the reflectivity of fiber gratings were 50% and 70% and 86%, and the length of external cavity was about 0.9cm. The measured result of FGECL showed that the side-mode suppression ratio (SMSR) was more than 35dB and the output power was larger than 1.5mW at the injected current 2 to 3 times of threshold current. Furthermore, the spectrums of fiber grating external cavity lasers were studied in order to understand the external laser characteristics.

Factors in fiber manufacturing procedures affect fiber¡¦s production, and the fiber quality will be affected accordingly. The residual stresses, in particular, have a significant influence on fiber quality, due to the mechanical strength and the refraction rate that has been changed. Mechanically, residual stresses may cause ruptures in the preform, reducing the intrinsic strength of the fiber and its durability; optically, it may also cause anisotropic distortions of the refractive index profiles. In the process of cooling under high temperature, fiber core and cladding will be compressed owing to the material difference and the residual stress will be in the fiber. Thermal conductance and thermal expansion coefficient contribute to the cracks on the interface and thus affect the refraction rate. Experiments have shown that quartz and Cr4+¡GYAG will rupture on the interface as a result of the huge thermal expansion coefficient. According to researches, stress in different directions will bring about fiber cracks or changes of the refraction rate. This paper mainly investigates the influence of material properties on the temperature field and thermal stress distribution in the cooling process of fiber and preform manufacturing by numerical simulations. The results show the preform temperature profile and the stress distribution in different directions. Also, through the stress distribution, the stress is known to be centered on the interface between core and cladding.