Dynamic two-axis curvature measurement using multicore fiber Bragg gratings interrogated by arrayed waveguide...

Area of Science:

• Optical sensing
• Fiber optic sensors
• Strain measurement technologies

Background:

• Fiber Bragg gratings (FBGs) are widely used for strain sensing.
• Interrogation of FBGs typically requires specialized equipment.
• Dynamic strain measurement demands high resolution and bandwidth.

Purpose of the Study:

• To demonstrate the use of arrayed waveguide gratings (AWGs) for interrogating FBGs.
• To achieve high-resolution dynamic strain measurements.
• To extend FBG sensing to differential strain measurements in multicore fibers.

Main Methods:

• Utilized AWGs for ratiometric interrogation of FBGs.
• Calibrated the system using static deflection experiments (+/-200 microepsilon).
• Implemented dynamic strain measurements on vibrating cantilevers and piezoelectric actuators.

Main Results:

• Achieved a strain resolution of 0.5 microepsilon at 2.4 kHz for single-core FBGs.
• Successfully measured dynamic differential strain between FBG pairs in multicore fibers.
• Determined arbitrary cantilever oscillations with 0.05 m(-1) curvature resolution at 1125 Hz.

Conclusions:

• AWG-based FBG interrogation is a viable method for high-resolution dynamic strain sensing.
• The technique is effective for both single-point and differential strain measurements.
• This approach offers a robust solution for structural health monitoring and dynamic analysis.