Research On The Graded-Index Plastic Optical Fiber

The purpose of this paper is to fabricate high quality and low-loss graded-index polymer optical fibers. After investigating the actuality of making the graded-index polymer optical fibers at home and abroad, Every facets of producing GI-POF were studied.Firstly the techniques of fabricating plastic optical fibers were introduced. The loss of POF, the loss mechanism and the method to decrease loss of POF were generally analyzed. So we decide to fabricate GI-POF by the method of interfacial-gel mass polymerization of methyl methacrylate (MMA).Secondly, some ways for purifying MMA such as two-stage rectification, dynamic melt crystallization and distillation-melt crystallization hybrid process were researched. A piece of advice to purify dopants using molecular distillation technique is presented. According to our practical situation, MMA was purified by two-stage rectification with loading materials added to rectifying column. The experimental result shows that the pureness of MMA increases clearly and the loss of GI-POF prepared using this MMA reduce evidently.For many experiments, using high pureness MMA, controlling polymerization temperature and polymerizing condition under high-pressure nitrogen gas and heat treatment after polymerization, a transparent preform without any bubble and blemishes was prepared. Then drawing this preform, GI-POF with diameter 0.8-1 .0mm was obtained.Because of the limitation of the experimental conditions and the shortage of the money, it is very regretted that we can't test the index profile and the loss of the GI-POF accurately. So we can't optimize the index profile by control the experimental condition. We hope that we will make progress continuously in the future researches and experiments.