Generalized and wavelength-dependent temperature calibration function for multipoint regenerated fiber Bragg grating...

Area of Science:

• Optical Engineering
• Materials Science
• Sensor Technology

Background:

• Regenerated fiber Bragg gratings (RFBGs) offer potential for high-temperature sensing.
• Conventional calibration of RFBG sensors is complex, costly, and challenging for multipoint arrays.

Purpose of the Study:

• To propose and demonstrate a new, simplified calibration methodology for RFBG temperature sensors up to 700 °C.
• To reduce the complexity and cost associated with calibrating RFBG sensor arrays.

Main Methods:

• Experimental determination of a generalized, wavelength-dependent temperature calibration function.
• Validation of the methodology using seven RFBG sensor elements.
• Comparison of measurement uncertainties with Class 1 thermocouples.

Main Results:

• A generalized calibration function was established for RFBGs fabricated with identical parameters.
• Each RFBG sensor requires calibration at only one reference temperature.
• Measurement uncertainties were found to be compliant with Class 1 thermocouples (< ±1.5 K).

Conclusions:

• The proposed method significantly simplifies the calibration of RFBG temperature sensors.
• This technique addresses challenges in calibrating spatially extended multipoint RFBG sensor arrays.
• The approach is adaptable to other fiber Bragg grating (FBG) temperature sensors, promoting wider adoption.