Study On Coherent Combining Of Multi-core Photonic Crystal Fiber Laser

Fiber laser displays wide application prospect and huge potential value due to its compact structure, high efficiency, high beam quality, good heat dissipation characteristics and so on. Compared to conventional fiber lasers, photonic crystal fiber laser has more advantages, such as: endlessly single mode transmission properties, adjustable dispersion property, high non linearity and high birefringence characteristics etc. So the study on photonic crystal fiber laser has important theoretical and practical significance.Theoretical calculation and experimental verification have been carried out for a fibre laser composed of 18 core photonic crystal fiber fiber. And the problems encountered in the process are studied and the solutions. The experiments using a 975nm semiconductor laser as the pump source, combined with the coupling structures system and mode analysis equipment designed independently, as well as calculation and analysis software written independently. And then coherent combining of 18-core PCF laser is studied.Main content:(1) The introduction of 18 core photonic crystal fiber used in the paper., and the research progress of photonic crystal fiber laser is introduced briefly in this paper.(2) Theoretical calculation and experimental verification have been carried out for the coupling system for the PCF laser.(3) The laser near field mode analysis equipment designed independently is introduced, and the monitoring results are analyzed in the paper.(4) The output of the PCF laser are analyzed. According to the 18-core PCF, the methods to achieve the core quality of coherent beam combination have been carried out. Then we improve the experiment.Creative points:The aspheric lens is used to eliminate the spherical aberration. Optical pathway is analyzed according to the variation regularity of Gaussian beam. For the aim of the fiber pump coupling, calculation have been carried out for the fiber 1:1 spatial coupler composed by calculation and analysis software written independently. It can be found that the coupler constituted with ellipsoid lens is more stable than that with hyperboloid lens; the 18 core photonic crystal fiber is dumped high efficiently by the above coupling system; The first that fiber laser output mode were observed and analyzed.by imaging method.