In order to improve coupling efficiency and maximal laser transmission energy density, lasers with Gaussian distribution and flat-top distribution were utilized to couple to optical fibers with different surface roughness. The coupling efficiency and damage threshold of the fibers were studied. The experiment results showed that for Gaussian distribution laser beam, optical fibers with higher degree of smoothness would get better coupling efficiency, but would suffer more damage inside the fiber. But for flat-top distribution laser beam, optical fibers with higher degree of smoothness would get both higher coupling energy and efficiency.
Two dichroic films were prepared to investigate their aging properties. Results indicate that the age-resistant property of dichroic films can be significantly improved by adopting lower deposition rate and relative high preposition temperature and being treated with stress removing annealing procedure. The correlation of reflective signal to transmission efficiency of igniting laser merely changes after aging for the designed age-resistant dichroic films.