Design and analysis of high power laser systems

Abstract

The thesis entitled "Design and Analysis of High Power Laser Systems", aims to study how to design, develop and analysis compact, reliable, efficient, and cost-effective high power fiber lasers. Different from other kinds of laser, fiber lasers can provide a very small beam spot and the beam diameter can be only a few several microns. Therefore, these fiber lasers can be used in different areas especially in industrial applications such as telecommunication, laser marking, laser cutting, optical sensing, etc. In telecommunication industry, new optical fiber networks such as CATV systems with passive optical network (PON) are commonly deployed. As a result, single mode fibers carrying several watts of optical power is used instead of multimode fibers. High power lasers can be achieved by using high power EDFAs. New technologies including double cladded fibers (DCFs), and pump combiner are used. Besides passive components, practical skills such as cladding pumping, and cladding mode stripping will be discussed. We will consider both continuous wave (CW) as well as pulse lasers. Pulse lasers by using waveguide ring resonators in passive mode-locking would also be analyzed. Use of ring resonator is a modern technology to build ultrashort pulse lasers. The pulse lasers can be used in high fiber laser systems as seed laser. The thesis is divided into three parts. Chapter 1 introduces the laser mechanism. Studies of the structures and characteristics of lasers including single frequency operation, narrow linewidth, and measurement of laser noise are also included. A narrow linewidth 1064 nm fiber laser which can work in spectroscopy is introduced. In Chapter 2, we discussed high power fiber amplifiers, including the designs, constructions, operations, and limitations of high power fiber amplifiers. Wideband fiber amplifier in 1 m range is report. The amplifier can work with the fiber laser mentioned in Chapter 1 in order to provide a high output power. Also, demonstration in LiDAR sensing application is given. Chapter 3 discussed pulse lasers, including advanced passive mode-locking by using waveguide ring resonators. Stabilizing of mode-locked laser is demonstrated. Also, 2 m range mode-locked laser by using mircoring resonator is reported. The progress as well as further development is given on Chapter 4.