Low-cost fabrication and characterization process for development of a sensitive optical fiber structure.

Abstract

The structure of silica single-mode fiber (SMF) must be modified in order to develop optical fiber-based biosensors. To reduce the diameter of the optical fiber, a low-cost chemical etching method is very popular. The proposed chemical etching method is a simple, rapid, and cost-effective technique for removing the silica cladding up to a desired diameter. In the laboratory, hydrofluoric acid (HF acid, 40% concentration) is used for etching. A variation on etching is also proposed and tested with 40% HF as well as with magnetic stirring at the different speeds. The etching experiments are also carried out at different temperatures. The etching results of silica fiber are presented through a step-by-step procedure using a rapid and resource-efficient method for the fabrication of optical fiber-based biosensors. The etched diameter characterization is done using a calibrated compound microscope. The sensing experiment with unetched and etched optical fiber is also performed for the detection of different concentrations of glucose biomolecules.