TENSILE MECHANICAL-PROPERTIES AND REDUCED INTERNAL-STRESSES OF POLYMER OPTICAL-FIBER

A few years ago, polymer optical fiber (POF) emerged worldwide as a means for short optical transmission. This fiber type is generally made of poly(methyl methacrylate) polymer and can be manufactured by a preform process using hot drawing in an oven. The mechanical properties, particularly the breaking stress, depend highly on the draw conditions. Recently, we have implemented the fabrication of very low diameter fiber, to take advantage of the electro-optic properties of stumps of such single mode fiber. It turned out that the drawing conditions cause undesirable internal stresses, which, in turn, yield unfortunate refractive index variations in the fiber. We observed that increased shearing speed during the drawing operation of low diameter threads did provide high modulus fibers. To overcome the occurrence of the huge shrinkage at T-g, we have found that temperature and length of the oven are critical parameters: an increase in the temperature and also the length of the oven for a given drawing speed has resulted in quality POF.