High precision micro-displacement fiber sensor through a suspended-core Sagnac interferometer.

Area of Science:

• Optics and Photonics
• Fiber Optic Sensing
• Interferometry

Background:

• Fiber optic sensors are crucial for precise measurements.
• Sagnac interferometers offer high sensitivity.
• Suspended-core fibers present unique optical properties.

Purpose of the Study:

• To develop and characterize a micro-displacement sensing system using a suspended-core fiber Sagnac interferometer.
• To investigate the sensing mechanism and performance limitations.
• To assess the system's suitability for low-cost applications.

Main Methods:

• Characterization of suspended-core fiber using optical backscatter reflectometry.
• Implementation of a Sagnac interferometer configuration.
• Evaluation of displacement sensitivity and temperature stability.

Main Results:

• The sensing system's sensitivity is primarily attributed to birefringence, with negligible core-cladding mode coupling.
• High precision micro-displacement measurements (~0.45 μm) were achieved.
• The system demonstrated excellent stability and high insensitivity to temperature variations.

Conclusions:

• The suspended-core fiber Sagnac interferometer is a viable platform for high-precision micro-displacement sensing.
• The system's stability, temperature insensitivity, and potential for low-cost fabrication make it attractive for various applications.
• Birefringence is the key factor enabling displacement sensitivity in this configuration.