A new method of index-profile measurement for optical fiber preforms - axially varying profile

摘要

In the optical fiber production process of MCVD or VAD method, perform rods are fabricated at the first stage and fibers are finally drawn from them. The index profile needed as an optical fiber is contructed in the perform and we expect the fiber structure must be of just scale down. Therefore, it is commonly employed at fiber development laboratolies or fiber industry to evaluate fiber properties by means of preform index profile measurement However, fibers under current development showing often more complicated and accuracy requirement are no longer accepted by conventional techniques. The authors have been made efforts to develop new techniques for preform index profile measurement. This report is one of the series of the work and proposes a new type of measurement for axially varying profile. In fact, performs fabricated with VAD-method have inherently axially varying profile but have not been seriously considered. Here, we call 'D-type' for the new technique and present its principle and results.