| 摘要 |
PURPOSE:To execute sure control at the time of stretching and to allow production at a good yield by lowering heating temp. on progression of stretching. CONSTITUTION:The heating temp. is lowered on progression of stretching at the time of production of the multiplexing/demultiplexing device. For example, the heating temp. in the stretching stage is so controlled that the welded part 2 of PANDA type double refractive optical fibers 1, 1 attains 1,700 deg.C when the diameter of the welded part measured from about is 125 to 100mum. The heating temp. is so controlled that the temp. of the welded part attains 1,500 deg.C when the diameter is 100 to 80mum, 1,500 deg.C when 80 to 60mum, 1,400 deg.C when 80 to 60mum, and 1,000 deg.C when 60 to 40mum. The resistance to the stretching increases gradually by lowering the heating temp. on progression of the stretching in such a manner and, therefore, the sure control at the time of the stretching is executed and the production at the good yield is possible. |
