Intensity-demodulated torsion sensor based on thin-core polarization-maintaining fiber

Area of Science:

• Optical sensing
• Fiber optics
• Instrumentation

Background:

• Accurate measurement of torsion is crucial for structural integrity monitoring.
• Existing torsion sensors may lack sensitivity or require complex demodulation.
• Integrated smart devices need robust and sensitive sensing components.

Purpose of the Study:

• To design and realize an intensity-demodulated torsion sensor.
• To investigate the sensing performance and temperature characteristics.
• To explore potential applications in aerospace engineering.

Main Methods:

• Utilized a polarization ring as the sensing element.
• Employed a thin-core polarization-maintaining fiber for demodulation.
• Obtained an intensity map of sinusoidal changes at specific wavelengths.

Main Results:

• Experimental results validated the theoretical analysis.
• Achieved maximum sensitivity of 0.29 dB/deg at 1584.6 nm.
• Measured minimum sensitivity of 0.10 dB/deg at 1510.2 nm.

Conclusions:

• The developed intensity-demodulated torsion sensor demonstrates effective performance.
• The sensor exhibits wavelength-dependent sensitivity.
• The proposed structure is suitable for integrated smart devices, such as for loose-screw detection in aerospace.