Double-cladding fiber laser and frequency doubling with PPLN

A highly efficient Yb doped double clad fiber laser, one end pumped by a 975nm diode attack source and generating up to 115.6 of CW output power at 1100nm is reported in this paper, the maximum optical-optical conversion efficiency is 79% and the slope efficiency is about 69%. The frequency doubling of the fiber laser is obtained with conversion efficiency of 6% by using PPLN as nonlinear optical material.