The Benefits Of Fiber—and Fiber Lasers

In geometrical terms, a fiber is simply a cylinder with a very high length-to-diameter aspect ratio; this gives fibers one of their most important properties, a very high surface-area-to-volume ratio. High strength along the fiber axis and the large surface area for bonding into matrices are the major reasons why fibers are so widely used as reinforcements. Interestingly, this same geometrical attribute of fibers, the highest possible surface-area-to-volume ratio, is also one of the main reasons fiber lasers have enjoyed such great success in the laser industry. In fiber lasers, the beam is actually generated within the fiber itself and because of this high surface area, the active fiber laser resonator has minimal cooling requirements. Similarly, the small fiber diameter in which the fiber laser beam is generated gives fiber lasers another advantage: only fundamental laser modes are allowed by the small diameter fiber. Therefore, fiber lasers produce the brightest commercially available, high-average-power near-infrared (IR) lasers, and this combination of brightness (focusability) turns out to be one of the many important reasons that they are becoming the most widely used laser source for processing composites.