Data processing optimization for TFBG spectral discretization and sensor coding

Tilted fiber Bragg gratings (TFBGs) offer several advantages for sensing applications; however, their interrogation entails complex spectral analysis with expensive instrumentation. As an alternative to conventional methods for TFBG signal processing, recently, it was proposed to discretize the TFBG spectrum to correlate a target measurand with a set of binary codes (bits) of “0” and “1”. In this work, we report on the optimization of such discretization process. We have generated such bits by discretizing different TFBG spectral ranges; the minimum number of bits needed to distinguish refractive index changes has been analyzed as well. It is demonstrated that the analysis of a narrow (~ 6 nm) spectral range of a TFBG immersed in different isopropyl alcohol (IPA) water mixtures can be sufficient to generate sets of bits that can be correlated with the mixtures.