Plastic optical fibre manufacture uses preform made with stage in which liquid compounds do not flow along it

摘要

The process for making plastic optical fibre with refractive index (RI) that varies between its center and periphery consists of preparing >=2 compounds (12,13) with different RI, each comprising polymer(s) and >=1 containing an ingredient that varies its RI and a reticulation starter. A preform maker (1) is filled with compounds to give preform having RI with given gradient; and extruded. The process for making a plastic optical fibre with a refraction index that varies between its center and periphery consists of preparing at least two liquid compounds (12, 13) with different refraction indices, each comprising at least one polymer and at least one containing an ingredient that varies its refraction index and a reticulation starter. A preform maker (1) is filled with the compounds to give a preform having a refraction index with a given gradient which is extruded to make the optical fibre. The production of the preform includes a stage in which there is virtually no flow of the compounds along the preform maker while creating a diameter compatible with extrusion. The compounds are kept separate within the preform, and their distribution is changed between the center and periphery by a mechanical treatment such as rotation or ultrasound vibration before extrusion.