Research Of Rare Earth Doped Micro-Structured Fiber For High Power Amplifier

Photonic crystal fiber (PCF) posses excellent optical features, such as endless single mode, controllable dispersion, high nonlinearity and large mode area,etc. The important applications in optical communication, manufacturing industry, military and biomedical. Yb-doped fiber can be used in the manufacture of high power fiber laser and laser weapons, etc. So LPF(large-pitch PCF) and core-doped PCF has become a hot topic of research in recent years.In this paper, we combine the theory of PCF and the COMSOL software to analyze fiber mode of two kinds of LPF and overlap factor of core-doped PCF. Specific details go as follows:1) Introduce the principle of optical propagation and excellent optical features of PCF. Introduce several theoretical research methods and its derivation process, such as Finite Element Method (FEM), Effective Index Model, Plane Wave Expansion Mthod(PWM), Finite Difference Time-Domain Method(FDTD),etc.2) Combine the COMSOL software to analog computation two kinds of LPF of three layers of air hole arranged hexagon PCF and double row of air hole arranged octagonal PCF. Analyze the influence of the effective refractive index and the large effective area when we change the air-hole diameter, pitch and the wavelength.3) Combine the COMSOL software to analog computation two kinds of core-doped hexagon PCF and core-doped octagonal PCF. Analyze the influence of the effective refractive index, the large effective area and overlap factor when we change the doped diameter, doped refractive index and the wavelength.The paper affords theoretical data for the futher of the LPF and core-doped PCF to some extent.