Orientation-free pressure sensor based on π-shifted single-mode-fiber Sagnac interferometer

Area of Science:

• Fiber optic sensing
• Interferometry
• Optical instrumentation

Background:

• Conventional pressure sensors often rely on high-birefringence polarization-maintaining fiber, which can be complex and sensitive to orientation.
• The need for simpler, more stable, and economical sensing solutions is critical in various industrial and scientific applications.

Purpose of the Study:

• To propose and analyze a novel orientation-free pressure sensor.
• To demonstrate the advantages of an all-single-mode-fiber (SMF) Sagnac interferometer for pressure sensing.
• To achieve high sensitivity and repeatability independent of external factors.

Main Methods:

• Development of a π-shifted all-SMF Sagnac interferometer.
• Active adjustment of a polarization controller to introduce an initial π shift.
• Utilizing the Jones matrix method for theoretical analysis.
• Experimental validation of the sensor's performance.

Main Results:

• The proposed sensor exhibits an intensity response independent of the device under test's birefringence orientation.
• The all-SMF structure offers improved simplicity, stability, and cost-effectiveness compared to conventional methods.
• Excellent repeatability and high sensitivity were achieved, simplifying data demodulation.

Conclusions:

• The novel orientation-free pressure sensor based on a π-shifted all-SMF Sagnac interferometer is a viable and advantageous alternative.
• This design overcomes the limitations of uncertain birefringence orientation, offering robust and reliable pressure sensing.
• The sensor's characteristics pave the way for easier and more accurate measurand demodulation.