Optical Strain Measurement with Step-Index Polymer Optical Fiber Based on the Phase Measurement of an...

Area of Science:

• Materials Science
• Optics
• Sensor Technology

Background:

• Polymer optical fibers (POFs) offer a larger elastic strain range than glass optical fibers (GOFs) for optical strain sensing.
• The phase response in single-mode polymer optical fibers (SM-POFs) is understood, but multi-mode fibers present unique challenges.
• Step-index polymer optical fibers (SI-POFs) are multi-mode, requiring consideration of modal dispersion, scattering, and attenuation effects on phase response.

Purpose of the Study:

• To investigate the impact of strain on step-index polymer optical fibers (SI-POFs).
• To develop and validate a novel model for SI-POFs that accounts for strain-induced effects.
• To analyze the responsivity of an optical strain sensor based on phase measurement in SI-POFs.

Main Methods:

• Developed a novel model for step-index multi-mode fibers (SI-MMFs).
• Expanded the model to incorporate strain-induced effects on refractive index and propagation angle.
• Simulated the strain responsivity of the SI-POF sensor and compared it with experimental data.
• Measured the far-field pattern of the SI-POF under varying strain conditions to validate findings.

Main Results:

• The developed model accurately simulates strain responsivity in SI-POFs.
• Experimental results validated the model's predictions.
• Demonstrated that the scattering behavior of SI-POFs is strain-dependent.
• Confirmed strain-dependent scattering by analyzing far-field patterns.

Conclusions:

• The novel model provides accurate strain sensing predictions for SI-POFs.
• Strain significantly influences the scattering characteristics of SI-POFs.
• This research enhances the understanding and application of SI-POFs in optical strain sensing.