Helical bend proof testing of optical fibers

Abstract From the Canadian patent

An optical fiber is proof tested by bending it relative to the fiber axis by a preselected amount, in all directions and at all locations along the length of the fiber. In one approach the, optical fiber is wrapped around a cylindrical mandrel in a helical pattern and drawn over the mandrel through its entire length. With the preferred helical angle of about 45 degrees two, wraps of the optical fiber around the mandrel ensure that all of the fiber will be bent in all directions. If a flaw exists in the optical fiber that would cause failure at any amount of bending below that of the preselected amount, this proof test will cause the fiber to fail so that the weak point may be eliminated.