Fabrication of Annular Waveguide layer capillary optical fiber preform and temperature field distribution during fiber draw

摘要

In this paper, we demonstrate a novel kind of annular waveguide layer capillary optical fiber perform which is composed of cladding, optical waveguide layer and central air hole. On the other hand, we fabricate a capillary optical fiber with an MCVD method using an advanced graphite furnace to heat and a specially made fiber drawing tower. The cross-section drawings of the optical fiber and the refractive index distribution are shown. Accordingly, we give cross section of capillary optical fiber and refractive index distribution profile. Moreover, by combining non-stable Fourier Heat-Conduction theory with fiber drawing technology, the simplified temperature field transmission model during capillary optical fiber preform drawing is established, and the temperature field distribution equation of the perform neck-down region is deduced. Meanwhile, we obtain the relationship between the temperature distribution of the neck-down region and the speed of preform feed and the furnace temperature through the numerical simulation. The conclusion shows that the high-qualified annular waveguide layer capillary optical fiber can be gotten when the temperature field distribution of the capillary optical fiber perform neck-down region is near to steady state, which well agrees with the experiment result.