Heat dissipation in kilowatt fiber power amplifiers

The heat dissipation and output power characteristics of kilowatt ytterbium-doped double-clad (YDDC) fiber power amplifiers are investigated through numerical modeling. Solutions to facilitate heat dissipation and reduce operating temperature in YDDC fibers under bi-directional end pump and distributed pump are presented and compared. It is shown that the heat dissipation issue in kilowatt fiber power amplifiers can be effectively solved by optimizing the arrangement of pump powers, pump absorption coefficients, and fiber lengths.