Analysis of the Absorption Efficiency of Graded-Index Double-Clad Fiber

摘要

The absorption efficiency of graded-index double-clad fiber lasers or amplifiers is investigated. As ray optics method is no longer valid for graded-index case, the mode analysis method is used in this paper. Calculated results show that absorption efficiency for a graded-index is higher than that for a step-index in symmetric case. In offset core case, the graded-index can achieve the same absorption efficiency with much smaller offset distance. The absorption efficiency for different graded-index profiles of the inner cladding is also calculated and compared.