Cryogenic Temperature Response of Reflection-Based Phase-Shifted Long-Period Fiber Gratings

• Published in: Journal of lightwave technology 2015-06, Vol.33 (12), p.2511-2517
• Main Authors: Martins, Raquel, Caldas, Paulo, Teixeira, Bruno, Azevedo, Joao, Monteiro, Jose, Belo, Joao H., Araujo, Joao P., Santos, Jose L., Rego, Gaspar
• Format: Article
• Language: English
• Subjects: Climate; Cryogenic temperature; cryogenic temperatures; Cryogenics; Diffraction gratings; Fiber gratings; Fibers; Germanium; Gratings (spectra); Long-period fiber grating; optical fiber sensor; Optical fiber sensors; Optical fibers; Reflection; Sensitivity; SQUIDs; Temperature sensors
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2014.2381236

In this study, we investigated the temperature behavior of phase-shifted long-period fiber gratings (PS-LPFGs) inscribed in two types of optical fiber: B/Ge and SMF28. The experiments were carried out from 5 to 305 K using a superconducting quantum interference device magnetometer. The average temperature sensitivity obtained of -0.43 nm/K for PS-LPFGs inscribed in the B/Ge fiber is one order of magnitude larger than for PS-LPFGs inscribed in the SMF28 fiber, in the 60-240 K range. Values ranging from -0.08 nm/K up to 0.2 nm/K were obtained in the 5-35 K temperature range, which are considerably better than previous results achieved for metal-coated FBGs and also for LPFGs inscribed in a similar B/Ge codoped fiber. Nevertheless, further work is required in order to correctly address sensor reliability.