| 摘要 |
<p>A method capable of producing an optical fiber preform of large diameter by reducing the eccentricity and non-circularity of cores in the rod-in-collapse method; an optical fiber preform which is improved in non-circularity even for large diameter and which has a complex refractivity construction; and an optical fiber which can be used as a dispersion compensation fiber. The rod-in-collapse process is performed wherein a glass rod is fixed in a glass pipe (or dummy pipe attached to the end) through an aligning jig. The fixing through the aligning jig is effected at one or both ends. The jig is, for example, in the form of a cylinder or a cylinder having one or more diametrically decreased portions. In the case of one-end fixing, it is desirable that the heating integration process be effected from the opposite end. The use of a material having a refractivity distribution for the core rod and glass pipe makes it possible to provide a complicated construction.</p> |
