 When the increase of the length of the fiber becomes limited by stimulated scattering, additional power scaling can be achieved by combining several fiber disk lasers into a stack.The spiral-coiled configuration is not the only possible arrangement; any other scheme of stacking of optical fibers with lateral delivery of pump can also be called a fiber disk laser, even if the resulting shape of the device is not circular.The term "fiber disk laser" applies to the concept of lateral delivery of pump to the active optical fiber rather than specifically to a disk-shaped device.