Linear FBG Temperature Sensor Interrogation with Fabry-Perot ITU Multi-wavelength Reference

• Main Authors: Minho Song, Hyoung-Jun Park
• Format: Article
• Language: English
• Published: MDPI AG 2008-10-01
• Series: Sensors
• Subjects: Fiber Bragg grating; Fabry-Perot filter; Fiber-optic temperature sensor
• Online Access: http://www.mdpi.com/1424-8220/8/10/6769/

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.