Fluoride Glass Optical Fibres

One of the most exciting prospects for optical fibres made from fluoride glasses is the possibility of providing long distance optical communication systems without the need for repeaters. This objective has stimulated much of the work into fluoride glasses over the past ten years, and has prompted the writing of this book. It has also emerged that fluoride fibres can transmit both visible and infrared energy (from about 0.5 to 5 ,urn) and that they have many applications outside the field of telecommunications. These include optical fibre sensors (particularly in remote infrared spectroscopy), laser surgery and fibre lasers. Several companies are now established in the field, and good quality fluoride fibres are available from sources throughout the USA, Europe and Japan. Moreover, the first commercial instruments based on fluoride fibres are finding their way to the market place and these fibres will undoubtedly form the basis of many more instruments yet to be developed. The work presented in this book represents the field both from an academic understanding of the materials and ways to convert them into fibre, and from a practical and commercial viewpoint. The principal author and some of the co authors are based at the British Telecom Research Laboratories in the UK.

Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and analyzing the fluoride glass raw materials. The sources of loss are considered in Chapter 6, while the work performed on the durability of fluoride glasses is analyzed in Chapter 7. Chapter 8 focuses on the effects of radiation on fluoride glasses. The last chapter deliberates the area of active phenomena such as doping of fluoride glasses with rare-earth elements for fluorescence and lasing, as well as frequency doubling. This publication is a good reference for students and researchers conducting work on fluoride glasses.

This book gives an overview on mid-infrared optical glass and fibers laser, it cover the underlying principle, historic background, as well as recent advances in materials processing and enhanced properties for rare earth doped luminescence, spectroscopy lasers, or optical nonlinearity applications. It describes in great detail, the preparation of high purity non-oxide IR glass and fibers to be used as mid-IR fiber laser and supercontinuum sources for optical fiber spectroscopy. It will be useful for academics, researchers and engineers in various disciplines who require a broad introduction to the subject and would like to learn more about the state-of-the-art and upcoming trends in mid-infrared fiber source development, particularly for industrial, medical and military applications.

This text brings together 29 papers presented at SPIE's Lasers and Materials in Industry symposium. They cover optical fibres and optical fibre materials.

This thesis is related to the spectroscopic and optical properties of doped optical fibers used as a laser amplifier for short laser pulses at high repetition rates emitting around 2 μm. Therefore short pulses created by a laser diode are amplified in thulium-doped optical fibers combining the benefits of a direct electronic control of the laser diodes' parameters and the robust setup of an optical fiber system that can easily be integrated. After the development of a high-current pulse generator especially adapted to the 2 μm laser diodes used, pulses of > 7 ns with peak powers in the Watt range could be generated. Due to the modal behaviour of these laser diodes only 2 mW of peak power could be launched into a single-mode fiber. By comparing different fiber glasses, a heavy metal fluoride glass could be identified as the optimum host for the ions thulium and holmium emitting around 2 μm. Due to the development of a numerical simulation tool based on rate equations and radiation transport equations the fiber parameters such as core diameter, fiber length etc. could be optimized, minimizing the amplified spontaneous emission (ASE) created inside the fiber. Based on this simulation a laser system consisting of cascaded fiber amplifiers could be realized. I emits short laser pulses (20-30 ns) at high repetition rates (up to 125 kHz) and peak powers of up to 5 kW. In contrast to Q-switched lasers the pulse width created is independent of the repetition rate. By using these pulses at 1.87 μm as an optical pump for a Cr2+:ZnSe laser, efficiencies of up to 22% could be reached at an emission wavelength of 2.5 μm.