High power photonic crystal fiber laser systems

We review the advantages of rare-earth-doped air-clad photonic crystal fibers for power scaling of fiber laser systems with excellent beam quality. Most recently, the output power of single-mode fiber lasers has been significantly increased (>500 W). Further power scaling is usually limited by damage to fiber end faces, thermo-optical problems or nonlinear effects. Microstructuring the fiber adds several desirable features to the fiber to overcome these restrictions.