Effect of core dislocation on performance of high power fiber laser

A theoretical model is established, and the effect of core dislocation on laser power and beam quality is analyzed theoretically. It is indicated that each mode in the core will lose a part of power when core dislocation occurred in the fiber, and the basic mode will couple to a higher order mode, which will reduce the beam quality. A high-power all fiber laser oscillation system was built using a 20/400 m double-clad ytterbium-doped fiber. The effects of core dislocation on laser performance were researched experimentally while the core dislocation occurred in cavity, out of cavity or both. It is found that the laser performance will be reducing when the core dislocation occurred either in cavity or out of cavity. The core dislocation occurred in cavity will lead to a big decrease of the laser power while the core dislocation occurred both in cavity and out of cavity will lead to a great decrease of the beam quality.