An optical device and method for varying an optical characteristic of an optical beam can include a plurality of optical fibers each having an input end, an output end, and a core, wherein each of the optical fibers has an effective area and a numerical aperture, and a beam-deviating component for moving at least one of the optical fiber input ends and the optical beam relative to each other such that the optical beam selectively enters the input ends one at a time and is transmitted out the output ends one at a time, wherein at least one of the effective areas and the numerical apertures varies among the plurality of optical fibers such that the optical beam transmitted out of the output ends has a varying optical characteristic.