Ld Pumped Nd <sup> 3 + </ Sup> Double-clad Fiber Laser And Its Multiple Characteristics Of The Study

The fiber laser which borns in the 60's and develop in 90's, bacause of its advantages in industrial processing, medical, communications, military and other fields, has been received a wide range of applications. Especially wavelength of visible light on high-power fiber lasers of Nd3+-doped double-clad fiber laser has important academic value and practical significance. The Nd3+-doped double-clad fiber laser and its harmonic characteristics have been researched from the aspects of theoretical and experimental in this article. The main research subjects list as follows:1. The double-clad fiber laser's research progress, and neodymium-doped double-clad fiber laser development process and current situation are reviewed. The characteristics of fiber laser, its applications, and its development trends are analyzed.2. The working principle of fiber laser, doped double-clad fiber characteristics of Nd3+ions, and the double-clad fiber characteristics and working principles are discussed. The different shape of inner cladding cross-section to the pump light absorption efficiency impacting is calculated from the. Theoretical. The methods of Double-clad fiber laser pumping commonly used in pump are analyzed, and the end-pumped and side-pumped coupling strengths and weaknesses are compared. The fiber types, the cavity-shaped structure and the pump means are. determined3. The LD-pumped green fiber laser is designed. Analysing the characteristics of pumping source and gain fiber. From the static rate equation, with mathematical software matlab simulated the relationship between the pump power and fiber length, and the experimental optimum fiber length of theoretical value is accessed. The coupling efficiency of aspherical lens coupling system is analysised. The harmonic theory is discussed, and analysis sevral nonlinear crystals which maybe use in the experiment. Given the experimental SHG program, and the various components of the coating and the situation are discussed in great detail.4. The experiment of LD pumped Nd3+-doped double-clad fiber laser is carried out based on theoretical research and numerical analysis. Using LD-pumped Nd3+-doped double-clad fiber, when the maximum pumping power of 18.7W, the near single-mode fiber-laser output with the center wavelength of 1088nm, bandwidth of less than 2nm, and maximal power of 1.68W is obtained, and the slope efficiency is 14.7%, the optical-to-optical efficiency is 12%, and the total conversion efficiency is 9%. It is using KTP crystal as a frequency crystal, and finally got 24mW, the center wavelength of 544nm green laser output and the experimental results are analyzed in detail.5. The summary and the prospect of the dissertation.