Static pure strain sensing using dual-comb spectroscopy with FBG sensors

Area of Science:

• Optical Engineering
• Spectroscopy
• Sensor Technology

Background:

• Fiber Bragg Grating (FBG) sensors are crucial for static strain sensing.
• Accurate characterization of FBG optical response is essential for reliable measurements.
• Temperature-induced frequency shifts can impact FBG sensor accuracy.

Purpose of the Study:

• To develop a precise method for characterizing FBG optical response for static strain sensing.
• To achieve a robust and pure strain sensing system by mitigating noise and temperature effects.
• To demonstrate high-resolution static strain measurement using the proposed technique.

Main Methods:

• Utilizing dual-comb spectroscopy (DCS) for FBG characterization.
• Digitally post-correcting mutual noise between the two optical combs.
• Employing a reference FBG to detect and compensate for temperature-induced frequency drift.
• Analyzing comb-resolved radio-frequency (RF) spectra.

Main Results:

• Achieved a stable central Bragg frequency with 0.315 kHz stability, outperforming the 1 kHz repetition rate difference.
• Successfully compensated for temperature-induced frequency shifts.
• Demonstrated a spectral sensitivity of 0.85 pm/µɛ.
• Attained a static strain resolution of 0.8 µɛ.

Conclusions:

• The proposed DCS method offers precise characterization of FBG sensors for static strain sensing.
• Digital post-correction and temperature compensation yield a robust and pure sensing system.
• The technique achieves high sensitivity and resolution for static strain measurements.