Tilted fiber Bragg gratings (TFBGs) have been demonstrated to be accurate refractometers as they couple light from the fiber core to the cladding. In our experiment, we changed the physical structure of the TFBGs to improve the refractive index sensing ability. One way is to stretch the grating section 5 mm longer. The result showed that not only the number of the cladding mode of the TFBG decreases but also the full width half-maximum (FWHM) of the cladding modes and core mode changes. The FWHM of the cladding mode of the tapered TFBG is more than twice than that of the original. However, the refractive index sensitivity of the tapered TFBG has no obvious improvement. Another way is to etch the grating section with 20% hydrofluoric acid solution. We find that the smaller the clad diameter, the higher the refractive index sensitivity of the TFBG.

Date Published: 14 November 2016
PDF: 7 pages
Proc. SPIE 10025, Advanced Sensor Systems and Applications VII, 1002506 (14 November 2016); doi: 10.1117/12.2247747

Published in SPIE Proceedings Vol. 10025:
Advanced Sensor Systems and Applications VII
Tiegen Liu; Shibin Jiang; Rene Landgraf, Editor(s)