PURPOSE: To prevent the lowering in strength of an optical fiber resulting from a fatigue phenomenon occurring in screening and guarantee the minimum strength thereof by carrying out a test in an atmosphere in which no fatigue phenomenon occurs.
CONSTITUTION: In the figure, 1 is a liquid nitrogen vessel, 2 is liquid nitrogen, 3 is feed rolls, 4 is draw-off rolls and 5 is an optical fiber. The optical fiber 5 is fed at a given speed by means of the feed rolls 3 having a pair of caterpillars and drawn off by means of the draw-off rolls 4. The drawing off speed is made faster than the feeding speed at a given rate so that a given tension is applied to the optical fiber. This is repeatedly performed to carry out a screening test. The section to apply a load to the optical fiber is maintained to be at a temperature less than 0°C by the liquid nitrogen in order to remove the fatigue phenomenon occuring when a load is applied.
KIMURA TAKAO
TAKAHASHI SHIROU
