All-Fiber, Directly Chirped Laser Source for Chirped-Pulse–Amplification By

All-Fiber, Directly Chirped Laser Source for Chirped-Pulse–Amplification by Ran Xin Submitted in Partial Fulfillment Of the Requirements for the Degree Doctor of Philosophy Supervised by Professor Jonathan D. Zuegel Department of Physics and Astronomy Arts, Sciences and Engineering School of Arts and Sciences University of Rochester Rochester, New York 2017 ii Dedication This thesis is dedicated to my father. He probably placed higher priority on my growth and education than his own career and did not spare any effort cultivating me. For that I am forever grateful. My father and I are similar as a person in many ways. However, a rapidly developing China and her growing connection to the world presented us very different paths for our lives. He only had five years of formal education. He struggled to teach himself to read and write, eventually becoming the only journalist for the local paper of my hometown and is now enjoying his retirement. I do feel that given better opportunities he could have achieved much more. If what I am doing can be called a certain level of achievement, it is through realizing the values he taught me. In this sense, I feel this is partial fulfilment of his potential. iii Biographical Sketch The author was born in Lingyuan, Liaoning province in northern China on March 5, 1983. He attended Nankai University in Tianjin, China from 2002 to 2006, where he received his Bachelor of Science degree. He majored in Physics and researched quantum entanglement of antiferromagnetic Heisenberg spin systems for his undergraduate thesis. He then started his graduate study at the University of Rochester, Department of Physics and Astronomy in 2006. For his graduate research, he first worked on experimental quantum optics in 2007 in Professor John Howell’s group. In 2008, he started to focus on developing a directly chirped fiber laser source for chirped-pulse– amplification systems. This research was supervised by Dr. Jonathan D. Zuegel in the Laboratory for Laser Energetics, University of Rochester. The author left University of Rochester in February 2014 to start his job at ASML-Cymer in San Diego, CA. iv Acknowledgements I would like to first thank my thesis advisor, Jonathan Zuegel, for his guidance through my research work. I am also deeply grateful for his patience with me as my thesis writing took an extra-long time since I left school for a new job in San Diego. I have received valuable support from many colleagues at the Laboratory for Laser Energetics, University of Rochester. I am thankful to Christophe Dorrer and Jake Bromage for numerous discussions on topics such as pulse characterization, pulse compression and pedestal suppression. Wade Bittle taught me basics of using RF instruments and building circuit boards. He has also supported me in building a negative feedback system for the fiber regenerative amplifier. I would like to acknowledge Ildar Begishev for operating the MTW system for DCLS pulse compression. I wish to thank Bob Cuffney and Rick Roides for discussions in electro-optics and fiber-optics, and also Andrey Okishev for discussions in regenerative amplification. I would like to thank Seung-Whan Bahk for getting me started in numerical modelling tools such as nonlinear optimization. I also wish to thank John Marciante and his students Lei Sun, Weihua Guan and Zhuo Jiang for discussions of fiber components and teaching me to use the fiber fusion splicer. I wish to thank my academic advisor John Howell for his guidance through my graduate research. I am deeply grateful to my family for their support through this journey. v Abstract Chirped-pulse–amplification (CPA) technology is widely used to produce ultra- short optical pulses (sub picosecond to femtoseconds) with high pulse energy. A chirped pulse laser source with flexible dispersion control is highly desirable as a CPA seed. This thesis presents an all-fiber, directly chirped laser source (DCLS) that produces nanosecond, linearly-chirped laser pulses at 1053 nm for seeding high energy CPA systems. DCLS produces a frequency chirp on an optical pulse through direct temporal phase modulation. DCLS provides programmable control for the temporal phase of the pulse, high pulse energy and diffraction-limited beam performance, which are beneficial for CPA systems. The DCLS concept is first described. Its key enabling technologies are identified and their experimental demonstration is presented. These include high-precision temporal phase control using an arbitrary waveform generator, multi-pass phase modulation to achieve high modulation depth, regenerative amplification in a fiber ring cavity and a negative feedback system that controls the amplifier cavity dynamics. A few technical challenges that arise from the multi-pass architecture are described and their solutions are presented, such as polarization management and gain-spectrum engineering in the DCLS fiber cavity. A DCLS has been built and its integration into a high energy OPCPA system is demonstrated. DCLS produces a 1-ns chirped pulse with a 3-nm bandwidth. The temporal phase and group delay dispersion on the DCLS output pulse is measured using temporal vi interferometry. The measured temporal phase has an ~1000 rad amplitude and is close to a quadratic shape. The chirped pulse is amplified from 0.9 nJ to 76 mJ in an OPCPA system. The amplified pulse is compressed to close to its Fourier transform limit, producing an intensity autocorrelation trace with a 1.5-ps width. Direct compressed-pulse duration control by adjusting the phase modulation drive amplitude is demonstrated. Limitation to pulse compression is investigated using numerical simulation. vii Contributors and Funding Sources This work was supervised by a dissertation committee consisting of Professors Jonathan Zuegel (advisor) and John Marciante of The Institute of Optics, and Professors John Howell and Nicholas Bigelow of the Department of Physics and Astronomy. The original idea of DCLS was from Jonathan Zuegel. The Yb-doped fiber amplifier in the fiber cavity was based on an amplifier built by John Marciante. The electrical components of the negative feedback system for fiber cavity dynamics control were built by Wade Bittle of the Laboratory for Laser Energetics, University of Rochester. The MTW laser system was operated by Ildar Begishev of the Laboratory for Laser Energetics for DCLS pulse amplification and compression. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, the University of Rochester, and the New York State Energy Research and Development Authority. This report was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or viii imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof. ix Table of Contents Dedication ............................................................................................................... ii Biographical Sketch ............................................................................................... iii Acknowledgements ................................................................................................ iv Abstract ................................................................................................................... v Contributors and Funding Sources........................................................................ vii List of Tables ....................................................................................................... xiii List of Figures ...................................................................................................... xiv 1 Introduction ...................................................................................................... 1 1.1 Chirped Pulse Amplification ..................................................................... 2 1.2 Directly Chirped Laser Source .................................................................. 7 1.3 Overview of Thesis Organization ........................................................... 11 2 Review of Existing Technologies Relevant to DCLS .................................... 13 2.1 Optical Pulse Stretcher and Compressor ................................................. 13 2.2 Yb-doped Fiber Laser Technologies ....................................................... 24 x 2.3 Regenerative Amplification Technology ................................................ 28 2.4 Polarization Maintaining (PM) and Polarizing (PZ) Fiber Technology . 34 2.5 Existing Literature for DCLS Technology .............................................. 39 3 Key Technologies for the Directly Chirped Laser Sources ............................ 44 3.1 LiNbO3 Phase Modulator ........................................................................ 46 3.2 Programmable Phase Control with

Load more