METHOD FOR CONTROLLING DIAMETER OF GRIN LENS FIBER AND FIBER DRAWING EQUIPMENT

摘要

Provided is a method for controlling the diameter of a GRIN lens fiber wherein the controllability of the diameter is improved when a GRIN lens fiber is drawn from a preform, and the production yield of a GRIN lens fiber having a diameter within a desired range is enhanced. A diameter (a) measured by a diameter measuring instrument (A) for measuring the outside diameter of a GRIN lens fiber under elongation in a heating furnace is controlled by controlling a drawing speed based on a diameter (b) measured, outside the heating furnace, by a diameter measuring instrument (B) for measuring the outside diameter of a GRIN lens fiber and a diameter (c) corrected by a diameter (a) which is the value of diameter (a) a predetermined time (T) earlier.