Novel devices and applications based on micro-processed optical fibers.

摘要

Optical fibers are ubiquitous in a vast number of fields ranging from telecommunication networks to biomedical applications, complex laser systems and assemblies amongst many others. Over the last few decades, the development of fiber fabrication technology has focused on introducing several degrees of design freedom in terms of fiber structure and performance. Further modification of the thickness of the fiber by tapering enables finer control over the wave-guiding abilities of the fiber and is the primary focus of this thesis. A tapering setup based on the radiation from a CO2 laser as the heat source along with automated step motor stages and scanning galvo mirrors, has been used for fabricating the tapered fibers.;During the past decade, significant advances have been made in the design and fabrication of microstructured fibers which rely on structural rather than compositional variations to provide light guidance. These fibers exhibit dramatic nonlinear effects on interaction with ultrashort pulses of high intensity. In this thesis, tapered holey fibers, or microstructured fibers with a solid core, have been studied numerically to obtain some insight into the effects of a continuously reducing core diameter on the process of supercontinuum generation. Tapered holey fiber devices have been designed and fabricated for incorporating into a self-referencing setup for the carrier-envelope phase stabilization of a mode locked Yb-fiber laser. A technique for structurally modifying such a device to improve its properties as a possible light source for a variety of applications has also been reported in this thesis.;A completely different regime of tapered fibers which includes reducing the diameter of the fiber to several micrometers over a few centimeters of length has been explored. A technique for splicing together two such fibers with loss has been developed for the first time. A method for forming optical loop resonators based on these tapered fibers with a spliced coupling region for structural robustness has been described and subsequent experiments and analysis prove that the incorporation of the splicing procedure for the fabrication of the resonator improves the performance of the device.