Physicochemical characteristics of the etching of optical fiber with a xylene buffer layer

An experimental study has been conducted to determine, using the chemical etching technique, the dependence of the cone length of lens-tapered optical fibers on the thickness of the xylene layer during the fabrication of preforms. The study demonstrates that the buffer layer thickness must be taken into account to obtain lens-tapered optical fiber preforms with cones of the required length and angle. The influence of etchant droplets forming on the optical fiber in an air environment during etching has been investigated. These droplets have been found to negatively affect the mechanical strength of the optical fiber due to the thinning caused by chemical reactions occurring on its surface. The effect of the buffer layer thickness on the droplet formation at the surface of the quartz cladding of single-mode optical fibers in an air environment has been established. Optimal values of the buffer layer thickness have been determined, these contributing to minimizing the adverse effects of etchant droplets in an air environment and to improving the reproducibility of obtaining a specific cone length when fabricating lens-tapered optical fiber preforms. This research provides valuable insights into optimizing the fabrication of lens-tapered optical fibers ensuring enhanced performance and reliability in practical applications.