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.