Theoretical And Experimental Research On Microstructured Fiber Laser Devices

The guided mechanisms and some fundamental properties of microstructured optical fibers (MOFs) are numerical investigated using the full-vectorial plane-wave expansion method and finite element method. Moreover, the applications of active and passive devices based on MOFs are explored in this dissertation. Especially, the fiber laser devices based on MOFs, including Yb3+-doped double-cladding MOF laser and MOF Raman amplifier, are theoretically and experimentally investigated. The main research contents and results are described as follows:1. The essential propagation properties and fundamental applications of MOFs are investigated firstly. We study the photonicband structure of the MOF cladding with triangular and honeycomb air holes lattices. Then the guided mechanisms of MOFs are demonstrated. The guided properties such as waveguide dispersion, effective modal area and nonlinearity for both index-guided MOF and photonic bandgap MOF are presented. By improving the conventional electric-arc fusion method, we have realized the splicing between two kinds of MOFs and SMF with relatively low splice losses. We have written fiber Bragg gratings in grapefruit MOF successfully. The multi-wavelength resonances are observed in the grating, and theoretical analysis shows that this phenomenon is caused by the resonances between core modes and cladding modes. The temperature and strain sensing property of a grapefruit MOF Bragg grating with multi-reflection peaks has been experimentally studied.2. The preliminary numerical analysis and experiment of high-power Yb3+-doped double-cladding MOF laser are carried out. The theoretical model describing the output properties of double-cladding MOF laser has been builded according to the MOF's extraordinary mode distribution. Using large-area-mode Yb3+-doped photonics fiber, we realized laser operation and analyzed its output properties. The laser is cladding pumped and the output power is 2.6W, with wavelength of 1074.5 nm and slope-efficiency 54%.3. The effects of gain and noise figure of Raman amplifier based on high nonlinear MOF are theoretically studied. Simplified theoretical model describing MOF Raman amplifier has been builded on our own, and simulation program has also been developed. The effects of gain and noise figure of MOF Raman amplifier with...