Abstract
The various aspects of optical fibers are investigated in relation to the advanced laser technology. The optical fiber is one of the lowest material in the optical materials. Low loss nature is attractive for the laser material because the laser performance is determined by the gain-to-loss ratio. The optical fiber has a unique nature of which optical parameter like refractive index and waveguide performance is strongly controlled by the anti-guiding or dispersion controlled structure. Fiber disk lasers are developed for the kW output and demonstrated 1020 W in cw mode. This is a typical result of a free-shape laser. The wide variety of expansion of this concept is discussed.
