MANUFACTURE OF PREFORM FOR OPTICAL FIBER

摘要

PURPOSE:To artificialy set a refractive index distribution in a vapor phase axially sticking method by applying mechanical vibration to a burner for forming glass fine particles. CONSTITUTION:In place of a conventional method for controlling a refractive index distribution using a differnce between starting material gases in the reaction rate and a diffference between laminate surfaces in the temp. distribution, a distribution difference is formed artificially. Parameter alpha (the equation) of alpha distribution used by Mr. Gloge et al. is considered as a method for quantitatively expressing a refractive index distribution. Mechanical vibration is applied to a burner to set the distribution so that alpha is made larger as compared to the case of a fixed burner. As the amplitude of the vibration is widened, alpha becomes larger and can be set at a desired value. For example, when a preform having large alpha is manufactured to enhance the coupling efficiency to a light source, this method is applied.