Ultrafast and temperature-insensitive strain interrogation using a PM-PCF based Sagnac loop interferometer and...

Area of Science:

• Photonics
• Optical Sensing
• Fiber Optics

Background:

• Strain monitoring is crucial in various engineering applications.
• Conventional fiber optic sensors often suffer from temperature cross-sensitivity, limiting accuracy.
• Photonic crystal fibers offer unique properties for enhanced sensing capabilities.

Purpose of the Study:

• To propose and demonstrate a novel, ultrafast, and temperature-insensitive strain interrogation system.
• To leverage the intrinsic thermal insensitivity of polarization-maintaining photonic crystal fiber (PM-PCF) for improved strain sensing.
• To achieve real-time strain measurement with high accuracy by eliminating temperature-induced errors.

Main Methods:

• Utilizing a Sagnac loop interferometer (SLI) incorporating a PM-PCF as the sensing element.
• Implementing linear wavelength-to-time (WTT) mapping using a dispersive element.
• Converting strain-encoded wavelength shifts to time shifts for real-time monitoring via oscilloscope.

Main Results:

• Experimental demonstration of the proposed strain interrogation system.
• Achieved an ultrafast interrogation speed of 100 MHz.
• Reported a strain sensitivity of -0.17 ps/με with ultra-low temperature dependence.

Conclusions:

• The developed PM-PCF based SLI system offers a promising solution for ultrafast and temperature-insensitive strain sensing.
• The integration of WTT mapping effectively converts wavelength shifts to time domain signals for real-time monitoring.
• This approach enhances measurement accuracy by mitigating the cross-sensitivity effect, paving the way for advanced structural health monitoring.