Investigation of the photosensitivity, temperature sustainability and fluorescence characteristics of several Er-doped photosensitive fibers

TL;DR

This study compares three types of Er-doped photosensitive fibers in terms of their photosensitivity, temperature resilience, and fluorescence properties, demonstrating their suitability for high-temperature optical sensors and fiber laser applications.

Contribution

It introduces and evaluates germanium/erbium, tin/germanium/erbium, and antimony/germanium/erbium fibers for optical sensing, highlighting their high-temperature stability and fluorescence characteristics.

Findings

All fibers exhibit satisfactory photosensitivity for FBG fabrication.

Sn/Er and Sb/Er fibers maintain FBG stability at temperatures up to 850°C.

A fiber laser using Sb/Er fiber demonstrates strong fluorescence emission.

Abstract

Three different types of Er doped photosensitive fibers, germanium/erbium (Ge/Er) fiber, tin/germanium/erbium fiber (Sn/Er) and antimony/germanium/erbium fiber (Sb/Er) have been manufactured and studied for use in optical sensor systems. Their characteristics of photosensitivity, the temperature sustainability of fiber Bragg gratings (FBGs) written into these fibers and the fluorescence emission from the Er dopant were investigated and compared. It has been shown in this work that these fibers all show a satisfactory degree of photosensitivity to enable the fabrication of FBGs and a significant level of fluorescence emission within the 1550 nm band for sensor use. The high temperature sustainability of the FBGs written into these fibers was investigated and seen to be quite significant at temperatures as high as 850 ^{\circ}C, in particular for the Sn/Er and Sb/Er fibers. A fiber laser using the Sb/Er fiber as the gain medium was demonstrated, giving evidence of the strong fluorescence emission from the Er dopant. These fibers are all suitable for use in a variety of sensing applications for the simultaneous measurement of temperature and strain by means of monitoring both the fluorescence characteristics and the peak wavelength shift of the FBGs formed in fiber laser sensor application.