Fiber laser are a special kind of diode-pumped solid-state laser. The fiber core is serving as an active medium and is therefore doped with rare earth ytterbium (Yb). The long-lifetime pumped diodes provide the light which activates the medium to produce and amplify the laser light inside the fiber. The pumped diodes are only activated during marking, thus enhancing their lifetime to more than 100,000 hours. This construction of the FAYb system with the active medium inside a waveguide (fiberglass) bypasses the thermal problems of conventional solid-state lasers when creating high powers. A simple air cooling is sufficient to achieve high peak pulse output values.