Yb ³⁺ -Doped Double-Clad Fibre Laser Pumped by Rectangular Inner Cladding

Abstract

A novel Yb3+-doped double-clad silica fibre with rectangular inner cladding was designed and developed by using the modified chemical vapour deposition process, solution-doping and optical machining all together. The dimensions of the inner cladding are 100×70 µm, and Yb3+-doped concentration in the core is about 0.24 wt.%. The operation of the fibre laser pumped by inner cladding is reported. The threshold of the laser is 34 mW. When the pump power launched is 141 mW, the laser output is 84 mW at the wavelength 1075.6 nm, and the slope efficiency is 77%.