Automated photosensitivity enhancement in optical fiber tapers

Abstract

An alternative technique that uses a flame-brush at high temperature to enhance UV light photosensitivity in an optical fiber is described. An extreme low-cost air aspirated propane-butane mini-torch is used, which produces a lower temperature flame than the one in the flame-brush original technique. It is shown that this change in the previous technique is also capable of improving photosensitivity and allowing the fiber Bragg grating imprinting process to be accelerated. Since the flame-brush photosensitivity enhancement process is designed to operate in an automated fiber taper rig, the process was evaluated in optical fiber tapers with different diameters. In this case, changes in photosensitivity are observed in the tapers in addition to the intrinsic photosensitivity occurring in the pristine fiber without being tapered.

Manufacture of Tapered Fibers and FBG Writing

“…For normal incidence of UV beam on the phase mask and fiber parallel mask, λ B is (2) where Λ PM = Λ / 2. It has already been observed that the reduction of the fiber diameters optimizes the grating writing process [5].…”

“…Applications in the chemical and biological subjects have been previously demonstrated [3], [4], [5], [6]. Bragg gratings written in tapered fibers (tFBG) can be obtained with arbitrary profiles [7] in the thinning region, allowing optimize the interaction with some sensor agent in the medium outside.…”