| 摘要 |
PURPOSE:The optimum shape of the growing part at the top end of the porous parent material is previously calculated from the correlation between 2 sepcific functions and the shape is controlled therewith to produce a parent material for optical fibers with a desired refractive index distribution. CONSTITUTION:The shape of the growing part 7 of the porous parent material 4 that is growing in a certain shape is taken in photographs, the contour of the photographs are directly put into diagrams (Figure-(a)) and simulated to the function F(r) of the equationIto give a factor alpha. In the meantime, a parent material 6 is formed by keeping the shape in the growing part as shown in the Figure-(a) and subjected to collapse treatment and its refractive index distribution is measured, thus the results are shown in Figure-(b). They are expressed by the equation II to give factor beta, thus obtaining the correlation between the shape of the growing part and the refractive index distribution. Then, utilizing the correlation, the shape of the growing part is controlled so that desired re fractive index distribution may be obtained by detecting the shape of the growing part, thus producing optical fiber parent material with desired refractive index distribution. |
