In-Line Fabry–Perot Etalons Based on Hollow-CorePhotonic Bandgap Fibers for High-Temperature Applications

Abstract

In this paper, we report a novel in-line fiber Fabry–Perot (F-P) etalon, consisting of a section of hollow-core photonic bandgap fiber (HC-PBGF) spliced between two single mode fibers. The fabrication process of such a sensor is simple and straightforward, including only cleaving and splicing. The sensing characteristics of the F-P etalon based on HC-PBGF, including high temperature, strain, bend, and transverse load, are fully investigated by experiments, for the first time to our knowledge. It is found that such a F-P etalon can be used under high temperatures of up to 600$ \,\,^{\circ}{\hbox {C}}$, and has a low cavity-length-to-temperature sensitivity of $\sim {1.4}~{\hbox {nm}}/^{\circ}{\hbox {C}}$, while it has a relatively high strain sensitivity of $\sim {5.9}~{\hbox {nm}}/\mu \varepsilon$. Moreover, this F-P etalon is insensitive to bend or transverse load. Furthermore, the long cavity length ($> {1}~{\hbox {cm}}$) of the sensor makes it suitable for multiplexing. These characteristics would make this HC-PBGF-based F-P etalon to be an excellent strain sensor or gas sensor for use in high-temperature environments.

© 2009 IEEE