Abstract: A system for machining and sizing optical fibers is described herein. The system uses a laser beam to machine oversized regions of a buffer material surrounding an optical fiber to create a coated optical fiber having a substantially uniform maximum outer dimension that is within a desired tolerance. The machining of the buffer material is accomplished by forming a substantially cylindrical laser beam having a hollow central portion and passing the optical fiber to be sized through the hollow central portion. The hollow central portion has a dimension or diameter substantially equal to a desired outer dimension or diameter for the optical fiber. Any discontinuities or oversized regions of buffer material outside the hollow central portion diameter will be contacted and vaporized by the substantially cylindrical laser beam.