A novel method to form plastic lensed fiber that could be used to manufacture in bulk quickly and raise the coupling efficiency is proposed. The way to form plastic lensed fiber is droping the mucilage on the fiber endface which is described in the reference, then the mucilage will be formed ball lens with surface tension. Next step is to force the ball lens to hyperbola shape with electric force. The method contains some restrictions including controlling the volume of the drop, the shrinking rate after curing, and the shape of the fabricated lens. The way improving the restriction of fabrication to achieve high coupling efficiency is described in this paper.

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Todays supercomputers employ the fastest processors incorporating the latest VLSI technology. Unfortunately, usable system performance is often limited by excessive interprocessor latency. To overcome this bottleneck, this thesis explores the use of all-optical path interconnection networks using a new topology defined by Coke Reed [31]. This work overcomes limitations of previous optical networks through a novel use of defection routing to minimize latency and allow more processors to collaborate on the same application and dataset. In this thesis research, the data vortex is formally characterized and tested for performance. Extra angles serve as virtual buffers to provide required system performance, even under asymmetric mode operation. The data vortex is compared to two well-known interconnection networks (omega and butterfly) using metrics of average latency and message acceptance rate. The data vortex is shown to outperform the comparison networks, with a 20-50% higher acceptance rate and comparable average latency. The impact of angle size is also studied, and a new, synchronous mode of operation is proposed where additional angles are added to increase the virtual buffering of the network. The tradeoff between virtual buffering and angle resolution backpressure is explored, and an optimal point is found at the 1:6 I/O to non-I/O (virtual buffering) angle ratio. The new mode and optimal angle count are used to form data vortex networks that perform as well as larger networks with fewer total nodes. Finally, hierarchical layering with data vortex clusters is proposed and compared to a single-level data vortex. In todays technology, similar performance is attained at high network communication locality loads (> 2/3), and a 19% latency reduction is obtained at the highest locality loads (> 95%) for current optical switching technology. For projected future technology, the clustered system is shown to yield up to a 55% reduction in latency for applications with 2/3 or better locality.

In this study, we will discuss the fabrication detail about the capillary optical fiber and microstructured optical fiber (MOF) from the preform manufacture to the drawing process and apply our capillary optical fiber in a temperature sensor device. First, we discuss the influence of the drawing parameters contribution for the fiber, and we will introduce how to design a preform and discuss how to keep our fibre geometry in drawing process by controlling the drawing parameters. For better fiber products, we need to make some important improvements such as fixing the preform geometry and designing the preform pressure or vacuum input path before the fiber drawing process. In the fiber drawing we want to control the fiber inner diameter and make the interval between three capillary tube disappear. We will solve these problems by different preform making methods or drawing tower hardware design and drawing parameter control. Now we can successfully make single ring hole MOFs by the capillary tube sealed method. But the hole structure is not as good as expectation. We will try to design a pressure and vacuum input device to replace the capillary tube sealed method. And help us to make better and more different MOF structures. We also used our capillary optical fiber to be a temperature sensor. We will describe the principle and the sensing sensitivity of our sensing device in this study. Our temperature sensing device shows a linear relationship between the temperature and operation wavelength, and the sensing sensitivity is 0.038nm/¢XC

Due to the fast growing communication need, the required capacity of the optical fiber network has been more than doubled every year. The technology breakthrough in dry fiber fabrication opens the possibility for fiber bandwidth from 1.3 £gm to 1.6 £gm. The fast increasing demand of communication capacity results in the emergence of wavelength division multiplexing (WDM) technology, enabling tens or even hundreds of channels with different wavelengths transmitted simultaneously on an optical fiber, which results in the need for ultra-broadband optical amplifier. Cr4+:YAG has a strong spontaneous emission spectrum covers from 1.3 £gm to 1.6 £gm. In addition, its absorption spectrum is between 0.9 £gm to 1.2 £gm, which matches the pumping wavelength of current erbium doped optical amplifier. Such fiber is, therefore, eminently suitable for optical amplifier applications. In this thesis, we introduce the development of ultra-broadband optical amplifier using the Cr4+:YAG double-clad crystal fiber, which is grown by the laser-heated pedestal growth (LHPG) technique. Try to use passive tence theoretical models and numerical simulations to know we can get more than 2 dB gross gain when signal propagations two times in Cr4+:YAG double-clad crystal fiber. With the butt-coupling method, a net gain of 0.0 dB is demonstrated at 1.3W bi-directional pump power and signal double pass in Cr4+:YAG double-clad crystal fiber at present. In the future, in order to reduce pump excited-state-absorption. We attempt to use clad-pump or side-pump scheme instead of core-pump scheme, to choose pumping wavelength at 925 nm instead of 1064 nm and to use side deposition of Yb2O3 and CuO . At the same time, we will continue to fabricate small-core-diameter Cr4+:YAG DCF to achieve a single-mode fiber and to extend its length to improve gain performance.

Modal birefringence and stress distribution measurement in doubt-clad rare-earth-doped fibers are reported. For example, doubt ¡Vclad ytterbium-doped fiber and doubt ¡Vclad neodymium -doped fiber. In this paper, I am interested in the effect of fabrication on birefringence of Cr4+: YAG double-clad crystal fiber. A knowledge of stress distribution in the fiber would indicate the origin of birefringence.Since fiber birefringence can be produced by different mechanisms.For example,stress-induced birefringence,geometrical anisotropy of a non-circular fiber core and inner-cladding, intrinsic birefringence, fiber bending and twist.To understand the origin of birefringence, I have obtained the stress distribution pattern in Polarization Optical Microscopy.Using scanning wavelength method (Phase Retardation), I set-up the system successfully and measured the group modal birefringence of bulk:YVO4 crystal and Cr4+ :YAG double-clad crystal fiber. I also used Jones matrix, Mueller matrix,stress optics law, photoelastic and mathematical formulas on the estimated modal birefringence to calculate the stress intensity distribution and interference light conditions and estimate the modal birefringence ,and then compared with other rare earth-doped fiber.

The most complicated and important step in optical packaging is coupling alignment. It is very difficult to handle too many parameters at the same time during the coupling alignment process. Most of the parameters are neglected in coupling alignment process, especially the parameters of angles. According to the analysis, we found that the misalignment of angles do not have influence on the position of highest coupling efficiency in XY plane. A 2+2 freedom searching method has been developed to reach the four axis coupling alignment. An automatic coupling alignment system has been carried out. And it can reach higher coupling efficiency and faster coupling alignment process.

In the fiber-optic modules packaging, the passive alignment can provide mass production, but it also results in low Electro-Optic performance. After using active alignment in packaging, the laser welding is often applied to assemble the module. However, the welding process cause a post-weld-shift (PWS) of fiber. And the laser welding machine is expensive, this will make the module packaging price hard to cost down. A major cost-reduction soldering fixing technique is developed to replace the laser welding. To determine the fabrication tolerances associated with the coupling of a laser diode and a single-mode fiber(SMF), the sensitivity of the coupling efficiency in both linear and angular offsets was measured. In this research, a fiber holder and a gripper have been developed for assembly. And active alignment is used to align the laser diode and SMF under computer control, whereupon a soldering fixing operation joins the fiber holder on the module. During the soldering process, the condition control was provided to keep the deflection steady. After the displacement compensating before soldering, the final displacement is less than 1 ㎛ which keeps the coupling loss within 3dB.

To get better EDFA performance, we have to improve the coupling efficiency of semiconductor laser diode(LD) and fiber optic; also, increase the LD¡¦s power to achieve. There are plenty of ways to have higher coupling efficiency out there. Some of them even can reach 90% or better coupling efficiency. However, because of light field property, high-power LD output will not be able to apply to high coupling efficiency structure. Therefore, using cascaded fiber can improve coupling efficiency and maintain its characteristic in high-power laser output environment. Cascaded fiber is connecting SMF and GIF together. Although cascaded fiber can increase high-power LD output of coupling efficiency, it has 5% to 10% of loss during manufacture because of the inspect error of melting surface. We use CCD to observe the cascaded fiber¡¦s melting surface. Then, we pair with special light source to do the examination. Thus, we can overcome the obstacle, do automatically manufacture of the cascaded fiber in a small area, and reduce the coupling loss of cascaded fiber.

Due to its easy growth, higher nonlinear coefficients, and better optical characteristics, LiNbO3 is broadly used as nonlinear crystal in laser system and wavelength converter in optical communication systems. In this thesis, we discuss the use of LHPG method to grow periodically poled LiNbO3 crystal fiber without metallic patterns. During the growth, micro-swing is managed to assist poling process, simultaneously we can understand and simulate the electric-field induced current. Using the relation between current waveform and micro-swing amplitude, we can quantify the micro-swing amplitude, and establish feedback control to enhance the stability during crystal fiber growth process. The achieved internal SHG conversion efficiency is 14.8 % with a quasi-phase matched period of 15.45 £gm. Besides promoting process stability and improving uniformity of domain inversion period, it is our hope that the relation between domain inversion and measured induced current can be clarified in the future. Due to the low Curie temperature of LiTaO3, it is expected that our experience on LiNbO3 can facilitate the development of periodic poling on LiTaO3.