Research On Optical Fiber Preform Manufacture And Its Properties

Since it was first suggested by Kao and Hockman in1966that low loss silica-basedfibers could be used as a transmission medium in the near infrared frequency, there has beentremendous progress in the development of fabricating lightguides which exhibit lowattenuation, high bandwidth, good dimensional control and excellent mechanical properties.Optical fibers that transmit light is the basis of fiber communication. Therefore any progressin fiber design and manufacture will make a great contribution to fiber communication.Fiber preforms play an important role in the whole fiber business, whose nearly70percents’ profits result from fiber preforms. So it is necessary for our country to have thetechnology for fabricating preforms. In1974, the MCVD process was first reported byMacChesney et al. in American AT%T laboratory (now Lucent). Then it has been widely usedbecause it is relatively easy to implement.In this paper we first introduced several processes for fabricating optical fibers and givea specific description of material choices, fiber design, tube considerations, particle depositionmechanism and collapse. Then based on MCVD process, we demonstrated a novel kind ofannular waveguide layer capillary optical fiber perform which is composed of cladding,optical waveguide layer and central air hole. Based on suspended particles dynamics, a finiteelement method is used to numerically simulate the fabrication of capillary optical fiberpreforms with the MCVD method. Moreover, by combining non-stable FourierHeat-Conduction theory with fiber drawing technology, the simplified temperature fieldtransmission model during capillary optical fiber preform drawing is established, Theconclusion shows that the high-qualified annular waveguide layer capillary optical fiber canbe obtained when the temperature field distribution of the capillary optical fiber performneck-down region is nearly in a steady state. Besides, the finite element method is also used tonumerically simulate the temperature field distribution during the fiber drawing process. Theoptimum drawing rate is obtained for preforms with various diameters and different furnacetemperatures. Finally, the properties and parameters of the annular waveguide layer capillaryoptical fiber were measured by experiments. In a word, it is quite significant to solve theproblems above for fiber design and manufacture.