Influence of fusion splice on high power ytterbium-doped fiber laser with master oscillator multi-stage power amplifiers structure

We have developed models to investigate the power properties of monolithic fiber laser with master oscillator multi-stage power amplifiers configuration. In the simulation the effect of optical characteristics of fiber fusion splice was considered, which was introduced by connecting fiber amplifiers. The theoretical modeling was established based on the classic theory of rate equations and the computational method was described in detail. On the basis of three high-power fiber lasers with different structures, we analyzed the splice loss and return loss, and how they influence the distribution of laser power in the system. The results showed that, on the present splicing level, both the enhancement of the pump capacity of fiber laser and the reduction of the quantity of power amplifier modules were effective strategies to accomplish fiber laser with tens of thousands of watts output.