Research on characteristics of co-linear side-pumping couplers with special double-clad fibers

摘要

The pump absorption properties in co-linear side-pumping schemes composed of a double-clad fiber with special inner cladding and a coreless pump fiber were investigated using the beam propagation method. The absorption efficiency of high-order modes is higher than that of low-order modes. The pump absorption efficiency enhances with the growth of the ratio of inner cladding diameter of main fiber to the diameter of pump fiber. Furthermore, the pump absorption with a non-circular inner cladding is higher than that with a circular inner cladding. In addition, the absorption in the system with a D-shaped inner cladding is hardly affected by the arrangement of the main fiber and pump fiber.