Curvature sensor enabled by fiber ring microwave photonic filter.

Area of Science:

• Photonics and Optical Sensing
• Microwave Photonics
• Fiber Optic Sensors

Background:

• Traditional spectral analysis limits curvature sensor resolution.
• Need for high-speed, high-resolution sensing in medical navigation and structural monitoring.

Purpose of the Study:

• To propose and validate a novel high-resolution curvature sensor.
• To overcome the resolution limitations of conventional fiber optic sensors.
• To demonstrate high-speed and multi-directional sensing capabilities.

Main Methods:

• Utilizing seven-core fiber Bragg gratings (7-Core FBGs) for sensing.
• Interrogating the 7-Core FBGs with a fiber ring microwave photonic filter (FR-MPF).
• Mapping optical wavelength shifts to microwave frequency shifts for enhanced resolution.

Main Results:

• Achieved a theoretical resolution of 0.26 × 10^-2 m^-1.
• Demonstrated a practical resolution of 0.65 × 10^-2 m^-1 at speeds over 100 Hz.
• Validated multi-directional sensing with low average relative errors (1.09% for curvature, 1.91% for direction).

Conclusions:

• The proposed system offers a significant advancement in curvature sensing resolution and speed.
• The compact and dynamic sensing system has strong potential for real-time applications.
• This technology can enhance precision in medical navigation and large-scale structural health monitoring.