Research of high-power multi-mode Er3+/Yb3+ co-doped double-cladding optical fiber lasers

In order to achieve much higher output power to satisfy the application requirements,the performances of erbium/ytterbium co-doped double-cladding fiber lasers(EY-DCFLs) are studied experimentally and theoretically.By using the EY805 model erbium/ytterbium co-doped multi-mode double-cladding fiber manufactured by INO,Canada as the gain medium,it is described that the output power is a function of the input pump power and fiber length.The maximum output power is about 3.5W by using a 1.8m fiber,with an optical to optical conversion efficiency of 31.8%.Numerical analysis of this EY-DCFL is also performed based on the rate and propagation equations.The calculated output powers of about 4.4W and conversion efficiency of 40% for the same fiber are a little larger than the experimental results.Then further optimization measures of the EY-DCFL are discussed,such as preparing of the fiber-end well,adding dichroic mirror at the output end and making fiber Bragg gratings directly in the fiber core.The above results are very important for the utilization and performance improvement of EY-DCFL.