Spectra profile expansion of Bragg wavelength on nano-particle embedded fiber-Bragg-grating

This article presents the results of a detailed study on the effects of spectra profile expansion of Bragg wavelength on the performance of the nano-particle embedded fiber-Bragg-grating (nano-EFBG) for sensing applications. The fiber-Bragg- grating (FBG) was coated by CdSe-nano-particle layers with various thicknesses (600–2000 nm) and bonded on substrates of epoxy or epoxy/Teflon with a large thermal expansion coefficient. With this embedding method, a variation of the line-width expansion of Bragg wavelength with cooling down FBG has been controlled. The nano-EFBG morphology was investigated by FE-SEM and the nano-EFBG sensors are studied in ambient from 77 K (liquid nitrogen) to 393 K. The expansion of spectral profile, which caused by transverse loading from nano-particle/epoxy layers, can be changed in the range of 0.1–1.3 nm between before and after cooling down. This result is for the strain-temperature sensors, but has the potential application in the FBG dispersion compensation devices and many other measurands.