Distributed high-temperature sensing based on optical frequency domain reflectometry with a standard single-mode...

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Metrology

Background:

• Accurate high-temperature sensing is crucial for industrial processes and safety monitoring.
• Standard single-mode fiber (SMF) is a cost-effective sensing element, but its performance at high temperatures requires optimization.
• Optical Frequency Domain Reflectometry (OFDR) offers high-resolution sensing capabilities.

Purpose of the Study:

• To demonstrate high-temperature distributed temperature sensing using standard SMF with OFDR.
• To develop and validate an algorithm for improving temperature demodulation accuracy.
• To evaluate the effect of annealing on fiber stability and temperature sensitivity.

Main Methods:

• Utilized standard single-mode fiber (SMF) for distributed temperature sensing up to 600°C.
• Employed Optical Frequency Domain Reflectometry (OFDR) with a spatial resolution of 2.5 mm.
• Developed and applied an instantaneous optical frequency resampling (IOFR) algorithm to correct laser nonlinearity.

Main Results:

• Achieved distributed temperature sensing up to 600°C over a 100.75 m fiber length.
• The IOFR algorithm successfully calibrated reference and measurement signals for accurate temperature demodulation.
• Annealed SMF exhibited superior temperature response stability compared to un-annealed SMF, with a sensitivity of 1.96 GHz/°C at 600°C.

Conclusions:

• Standard SMF can be effectively used for high-temperature distributed sensing with OFDR.
• The IOFR algorithm enhances the accuracy and reliability of temperature measurements.
• Annealing improves the long-term stability of SMF-based temperature sensors operating at extreme temperatures.