We have proposed an optical pulse correlation remote sensing technique, which has the advantages of high accuracy and good response linearity. To eliminate the impact of polarization fluctuation on sensing signals, we use a polarization scrambled pulse train (PSP), in which the polarization state of each pulse is randomized. We measure the stability of sensing signal under polarization fluctuation in optical pulse correlation sensing with the PSP light and obtain good stability. Moreover, we demonstrate tensile strain measurement using the optical pulse correlation sensing with the PSP and confirm the linear response to the tensile strain even under polarization changing.
We propose a region selectable gas sensing system, which can address gases of single and/or different species at multilocations.
This technique is based on optical spectroscopy of each selected numerous absorption lines of gas. Primary
experiment using fiber-optic absorption sensors, sensing regions and region selectors are demonstrated. Specific FBGs
are employed to reflect the selected spectrum for each sensing region. FBG monitor what encloses the tunable light
source and spectrum analyzer works as selected gas and region absorptions measurement. Absorption ratio was estimated
which indicates that the technique is applicable in lightweight fiber optic wide-regions gas sensing.