Dissertation > Excellent graduate degree dissertation topics show

The Laser Coupling and Beam Evolution of the Fiber-Based High-Energy High-Power Pulsed Laser System

Author: HuangZhiHua
Tutor: HuSiDe
School: Tsinghua University
Course: Nuclear Science and Technology
Keywords: fiber laser fiber amplification network high energy density physics lasercoupling beam evolution
CLC: TN253
Type: PhD thesis
Year: 2013
Downloads: 22
Quote: 0
Read: Download Dissertation

Abstract


The demand in high energy density physics research, including the laser-driven in-ertial confinement fusion and high energy particle collider based on the laser plasma ac-celeration, is a major power to push the development of the high-energy high-power laserdriver forward. Because of the ultra-low energy conversion efficiency of the laser driverbased on the Xenon lamp pumped large-aperture Nd-doped glass bulk medium, it can’tmeet the efficient, repetition rate operation requirements for the future laser drivers ofthe inertial fusion energy and high-luminosity high-energy particle collider facilities. Thehigh-energyhigh-powerpulsedfiberlasersystembasedonthefiberamplificationnetworkconcept inherits the features and advantages of the fiber laser which make it a promisingscheme for the future laser driver.In this thesis, the integrated configuration and basic concepts of the high-energyhigh-power pulsed fiber laser system are analyzed and three major constraints, i.e. lasercoupling requirement constraint, single fiber output capability constraint and fiber beamcombining tolerance constraint, are proposed. The key scientific and technological is-sues in this system are briefly summarized. A theoretical model is proposed to analyzethe laser coupling of numerous fiber outputs. The requirements for the mode field diam-eter and output energy from a single-core fiber are given for the mega-joule class laserdriver. Intensity distribution on the target under coherent and incoherent beam combiningconditions is numerically researched. For exploring the ultimate limitation of the outputpeak power from a single-core fiber, a nonlinear beam propagation numerical model isbuilt to model the self-focusing effect in ultra-large-mode-area highly-multimode fibers.Variation of the self-focusing length of the fundamental mode, higher order mode andthe summation of numerous modes with the core diameter and peak power are revealed.The results show that, requirements of the mode field diameter and output energy of thesingle-core fiber according to the laser coupling constraint are one order of magnitudelarger than that can be achieved with the state-of-the-art technology. Therefore, novelultra-large-mode-area waveguide structure and methods to suppress the self-focusing ef-fect requires further research.For describing the pulse evolution process in the single fiber propagation and am- plification chain which is the basic element of high-energy high-power pulsed fiber lasersystem, a combined model which couples the dynamic laser rate equation and Ginzburg-Landau equation is proposed. The incoherent pump process and coherent temporal-spectral evolution of the signal pulse can be described via this model simultaneouslywhichenlargesthedescriptionscopeoforiginaltwomodels. Asapreliminarydemonstra-tion of the single fiber propagation and amplification chain, an all-fiber pulsed amplifiersystem employing the large-mode-area photonic crystal fiber is designed and experimen-tally demonstrated based on the general design principles of the pulsed fiber amplifiersystem. The cleaving and splicing technologies of the large-mode-area photonic crystalfiber are explored. Near milli-joule energy is obtained for10ns square seed pulse whilethe fundamental mode operation is achieved.

Related Dissertations

  1. Thulium-doped Fiber Laser Technology,TN248
  2. Study on the Laser Characteristic of Tm3+-doped Double-cladding Fiber,TN248
  3. Research of Spectral Beam Combining Technology for High Power Fiber Lasers,TN248
  4. Study on Narrow-linewidth Yb-doped Fiber Laser,TN248
  5. Study of Pulse Tunable Fiber Laser,TN248
  6. Investigation of 2μm Tm3+-Doped Double-Clad Fiber Lasers,TN248
  7. Process Research on Fiber Laser-MIG Hybrid Welding Medium Thickness Aluminum,TG456.7
  8. All-Fiberized Passively Q-switched Fiber Laser and Supercontinuum Generation,TN248
  9. Study on Beam Shaper Based on High-power Fiber Lasers,TN248
  10. All Fiberized Linearly Polarized Pulsed Yb Fiber Laser with High Repetition Rate,TN248
  11. Brillouin erbium-doped single-mode fiber laser and its application,TN248
  12. Passively mode-locked fiber laser and its dispersion management,TN248.1
  13. Research of MOPA-frame 1550nm Passively Mode-locked Fiber Laser,TN248
  14. Study on the Target-In-the-Loop Adaptive Optics Systems,TN249
  15. Research of Fiber Laser Pumped Picosecond Optical Parametric Oscillators,TN752
  16. Theoretical and Experimental Research on 1.06μm Yb3+-doped Phosphate Fiber Laser,TN248
  17. Technology Research on Laser Drilling by Fiber Laser Marker,TN249
  18. Study on Millimeter-wave Generation Technology Based on Distributed Bragg Reflector Fiber Laser,TN248
  19. Research on C+L Band Multi-wavelength Fiber Laser,TN248
  20. Theoretical and Experimental Study of Pulse Pumped Ytterbium-doped Double-clad Fiber Laser,TN248
  21. Influence of Pump Laser Line Width in Frequency Conversion,TN248

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Photonics technology,laser technology > Optical waveguide and integrated optics > Fiber optic components
© 2012 www.DissertationTopic.Net  Mobile