High sensitive and large dynamic range quasi-distributed sensing system based on slow-light π-phase-shifted fiber Bragg gratings
K.M. Dwivedi , Tomasz Osuch , G. Trivedi
AbstracttIn this paper, we theoretically analyze the slow-light �-phase-shifted fiber Bragg grating (�-FBG) andits applications for single and multipoint/quasi-distributed sensing. Coupled-mode theory (CMT) andtransfer matrix method (TMM) are used to establish the numerical modeling of slow-light �-FBG. Theimpact of slow-light FBG parameters, such as grating length (L), index change (�n), and loss coefficient(˛) on the spectral properties of �-FBG along with strain and thermal sensitivities are presented. Sim-ulation results show that for the optimum grating parameters L = 50 mm, �n = 1.5×10−4, and ˛ = 0.10m-1, the proposed slow-light �-FBG is characterized with a peak transmissivity of 0.424, the maximumdelay of 31.95 ns, strain sensitivity of 8.380 ��-1, and temperature sensitivity of 91.064◦C-1. The strainand temperature sensitivity of proposed slow-light �-FBG is the highest as compared to the slow-lightsensitivity of apodized FBGs reported in the literature. The proposed grating have the overall full-widthat half maximum (FWHM) of 0.2245 nm, and the FWHM of the Bragg wavelength peak transmissivityis of 0.0798 pm. The optimized slow-light �-FBG is used for quasi-distributed sensing applications. Forthe five-stage strain quasi-distributed sensing network, a high strain dynamic range of value 1469 �� isobtained for sensors wavelength spacing as small as 2 nm. In the case of temperature of quasi-distributedsensing network, the obtained dynamic range is of 133◦C. For measurement system with a sufficientlywide spectral range, the �-FBGs wavelength grid can be broadened which results in substantial increaseof dynamic range of the system.
|Journal series||Opto-Electronics Review, ISSN 1230-3402, (N/A 70 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||�-FBG; Slow-light; Sensitivity; Quasi-distributed sensing; Transfer matrix methoda|
|Score||= 70.0, 01-01-2020, ArticleFromJournal|
|Publication indicators||= 0; = 0; : 2017 = 1.16; : 2018 = 1.438 (2) - 2018=1.58 (5)|
|Citation count*||1 (2020-04-05)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.