Ultrahigh-Temperature Regeneration of Long Period Gratings (LPGs) in Boron-Codoped Germanosilicate Optical Fibre

Sensors

Wen Liu¹  Kevin Cook¹  John Canning¹ 

[1] interdisciplinary Photonics Laboratories (iPL), School of Chemistry, The University of Sydney, Sydney NSW 2006, Australia; E-Mails:

关键词: regenerated gratings;    long period gratings;    fibre optic sensors;    strain sensitivity;    temperature dependence;    transition temperature;    melting temperature;    glass relaxation;   

DOI  :  10.3390/s150820659

来源: mdpi

【 摘 要 】

The regeneration of UV-written long period gratings (LPG) in boron-codoped germanosilicate “W” fibre is demonstrated and studied. They survive temperatures over 1000 °C. Compared with regenerated FBGs fabricated in the same type of fibre, the evolution curves of LPGs during regeneration and post-annealing reveal even more detail of glass relaxation. Piece-wise temperature dependence is observed, indicating the onset of a phase transition of glass in the core and inner cladding at ~500 °C and ~250 °C, and the melting of inner cladding between 860 °C and 900 °C. An asymmetric spectral response with increasing and decreasing annealing temperature points to the complex process dependent material system response. Resonant wavelength tuning by adjusting the dwell temperature at which regeneration is undertaken is demonstrated, showing a shorter resonant wavelength and shorter time for stabilisation with higher dwell temperatures. All the regenerated LPGs are nearly strain-insensitive and cannot be tuned by applying loads during annealing as done for regenerated FBGs.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.