The equidistantly spaced multi-passbands of a Fabry-Perot ITU filter are used as an efficient multi-wavelength reference for fiber Bragg grating sensor demodulation. To compensate for the nonlinear wavelength tuning effect in the FBG sensor demodulator, a polynomial fitting algorithm was applied to the temporal peaks of the wavelength-scanned ITU filter. The fitted wavelength values are assigned to the peak locations of the FBG sensor reflections, obtaining constant accuracy, regardless of the wavelength scan range and frequency. A linearity error of about 0.18% against a reference thermocouple thermometer was obtained with the suggested method.
To improve measurement accuracy of spectrally distorted fiber Bragg grating temperature sensors, reflection profiles were curve fitted to Gaussian shapes, of which center positions were transformed into temperature information. By applying the Gaussian curve-fitting algorithm in a tunable bandpass filter demodulation scheme, approximately 0.3 degrees C temperature resolution was obtained with a severely distorted grating sensor, which was much better than that obtained using the highest peak search algorithm. A binary search was also used to retrieve the optimal fitting curves with the least amount of processing time.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.