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.

Optical add/drop multiplexer (OADM) and optical wavelength cross-connect (WXC) are two key components to enable greater connectivity and flexibility in dense wavelength division multiplexing (DWDM) networks. Fiber Bragg grating (FBG) based components have several inherent advantages such as compact, low-insertion loss, high reflectivity, no-linearity effect, polarization insensitivity and wavelength tunability. We experimentally investigate the system power penalty induced by the chromatic dispersion of the FBG as a function of the wavelength detuning of the reflection spectrum for 10 Gb/s signals, which was reflected by cascade of FBGs. Such power penalty limits the number of cascaded gratings and restricts the allowable range of wavelength detuning. In our experiments, we have used several FBG filters with 3-dB bandwidth of 0.43 nm. According to the experimental results, power penalty increases from the central wavelength to the edge wavelength of the reflection spectrum. There are 0.4 dB and 7 dB power penalty for one single FBG and ten cascaded-FBG filter, respectively, when the central wavelength was detuned to ¡Ó0.2 nm and ¡V0.1/+0.14 nm. This study result may give a design guideline of fiber grating-based optical add-drop multiplexers or optical wavelength cross-connects in DWDM nodes.

The rapid developments in optical and electronic technologies have accelerated developments of solid state laser technology. The diode-pumped solid state laser has the merits of the diode laser, such as compactness, low cost, and the merits of the solid state laser, such as high laser quality, high conversion efficiency, long lifetime, and simple structure. There use in laser applications is very cost-effective in terms of material consumption, which is typically one-thousandth that of bulk material. In addition, heat dissipation in the gain medium can be significantly alleviated because highly heat-conductive material can be applied to the circumference of the crystal fiber. So, it was applicated in electronics, communication and medicine widely. The laser-heated pedestal growth (LHPG) method is now a well-established technique for the growth of single-crystal fibers. It is crucible free and can therefore produce high-purity, low-defect-density single crystals. Interface loss is one of the dominant factors that reduce the efficiency of crystal fiber lasers, although cladding with a dielectric coating or in-diffusion of the gain core has been utilized to suppress this interface loss. Using a gradient-index Nd:YAG crystal fiber with peak Nd concentration up to 1.6-atm.%, we recently demonstrated a laser power of 145 mW and slope efficiency 28.9%. Peak Nd concentration up to 3.6-atm.% Nd:YAG crystal fiber with a 20-um core was grown, which could eliminate the interface loss and enhance the efficiency of crystal fiber lasers to be compatible with bulk solid-state lasers.

This paper presents a novel active-alignment technique to fabricate one-dimensional optical fiber array. The advantages of this technique are providing simple structure on silicon- based optoelctronic device and individually adjusting relative position error of fiber array and laser diode array. The way to adjust fiber displacement is applying electric force to pull the adhesive which used to fix fibers and microholders. Then the adhesive has adhesive force with fiber surface that bring fiber moving away from its original position. The method has to consider some issues including choosing the adhesive viscosity, controlling adhesive volume in the microholder, confirming adjusting precision of fiber displacement, compensating the fiber Offset after curing. So we can obtain the minimum adjusting precision 0.5£gm and control the fiber traveling distance at ¡Ó0.4£gm. The way to improve those issues of adjusting the fiber array to achieve the best coupling position is described in this paper.

Abstract For the requirements of high-speed signal transmission has been increasing in the optical communication system ,so the fiber array in the communication system has a lot of advantages which can not be replaced. But the loss of coupling efficiency is a difficult problem as the distance of communication is getting longer and longer. The packaging quality of the fiber array module. In order to increase the transmission and the coupling efficiency, we produce the high precision to reach the goal. This paper use adhesive bonding technology to packageing of the fiber array module. But the adhesive had shrinkage and strength two problem. This paper presents a novel height and strength control strategy is constructed to fabricate one-dimensional optical fiber array. For the height,a active-alignment technique is used and shrinkage control and pick adhesive parameter can improve accuracy to displacement distance is below 1£gm in the work tempeture.For the strength of the adhesion¡Aa way to use different kind temperature in the work can add adhesion's strength. After work use to replace temperature in order to add strength. All the improvements of the above packading technologies are proposed to raise or keep the performance of the fiber array module.So,the error between theories and experiments can be minimized.Meanwhile,a high stability and repeatability of the packaging can be achieved due to the automation of the positioning force sensing,andinspection.

Applying laser near-field wavefront reconstruction, we have discussed the coupling mechanism of the laser and optical lensed fiber. The coupling of the laser and optical lensed fiber is in the near-field range. In order to discuss the coupling mechanism of the laser and optical lensed fiber, we had to measure laser beam in near-field(including intensity and phase).The laser near-field intensity could be measured directly with an objective and a CCD camera. Because the laser spot size was too small, it was difficult to measure the laser near-field phase directly. Therefore, we used the phase retrieval algorithms, intercepting two groups of laser near-field intensity distribution plane to calculate laser near-field phase distribution. Combining laser near-field intensity distribution and phase distribution, we could rebuild laser beam in near-field. Lensed fiber is fabricated by means of grinding and fusing. We measured the coupling efficiency of the lensed fiber and laser diode(the wavelength of laser beam is 980nm), and simulated the surface of the lensed fiber with software. Applying beam propagation method, we could calculate the laser near-field distribution which propagated through lensed fiber, and cooperate the coupling efficiency of the lensed fiber and laser diode to explain the coupling mechanism. In summary, we discovered that the lensed fiber in the course of the coupling mechanism of the laser and optical lensed fiber changed the laser near-field phase from a bending curved surface into a flat curved surface just like the phase of plane wave, and it also improved the coupling efficiency.

No description available.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xii, 153 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 129-136).

Thesis (Ph. D.)--Lehigh University, 2002. / Includes vita. Includes bibliographical references (leaves 164-175).

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Powers, John P. Second Reader: Michael, Sherif. "September 1990." Description based on title screen viewed on December 17, 2009. DTIC Descriptor(s): Semiconductor lasers, amplifiers, output, optical properties, environments, degradation, monitoring, communication equipment, modular construction, alternating current, optical communications, lasers, thermistors, drives, transmitters, power, circuits, direct current, photodiodes, analog systems, diodes, fiber optics. DTIC Identifier(s): Semiconductor lasers, intensity modulation, theses. Author(s) subject terms: Semiconductor laser diode; thermoelectric cooling; laser diode driver; intensity modulation. Includes bibliographical references (p. 103-105). Also available in print.