Theoretical analysis of multipoint pump Yb3+-doped double-clad fiber lasers

A wide-scope multipoint pump Yb3+-doped double-clad fiber laser model including end-pump reflectivity is proposed in detail. The results show that the optimal fiber length decreases as pump reflectivity increasing at multipoint forward or backward pump. The output powers reach to the maximum value when both the input and output end-pump reflectivity chooses the maximum value. The optimum fiber length increases and corresponding maximum output power decreases as side pump point numbers increasing.