Method for drawing grin lens fiber
When drawing of a GRIN lens from a preform is started, wastage of the preform is reduced and the amount of time taken from the start of elongation of the preform to the start of winding is reduced. A preform, to a lower end of which a weight formed of silica is fused, is set in a heating furnace, and drawing of the preform is started by heating a fused portion where the preform and the weight are fused to each other. This can reduce wastage of the preform. Since an elongation speed of the preform is increased by the weight of the weight, the amount of time taken from the start of the elongation of the preform to the start of winding can be decreased.
1. A method for drawing a GRIN lens fiber, the method comprising:
positioning a preform in a heating furnace, a weight being fused to a lower end of the preform at a fused portion, such that the fused portion is positioned 1 mm to 3 mm above a maximum temperature portion of the heating furnace; and
starting drawing of the preform by heating the fused portion where the preform and the weight are fused to each other and allowing a force of gravity on the weight to draw the preform.
2. The method of claim 1 , wherein the weight is made of silica.
3. The method of claim 2 , wherein the weight has a rod shape with a circular cross section.
4. The method of claim 3 , wherein the weight weighs 5 to 15 grams.
5. The method of claim 1 , wherein the weight has a rod shape with a circular cross section.
6. The method of claim 5 , wherein the weight weighs 5 to 15 grams.
7. The method of claim 1 , wherein the weight weighs 5 to 15 grams.
8. A method for drawing a GRIN lens fiber, the method comprising:
positioning a preform in a heating furnace, a weight being fused to a lower end of the preform at a fused portion, such that the fused portion is positioned above a maximum temperature portion of the heating furnace; and
starting drawing of the preform by heating the fused portion where the preform and the weight are fused to each other and allowing a force of gravity on the weight to draw the preform.
9. The method of claim 8 , wherein the weight is made of silica.
10. The method of claim 9 , wherein the weight has a rod shape with a circular cross section.
11. The method of claim 10 , wherein the weight weighs 5 to 15 grams.