Polymer planar Bragg grating sensor for static strain measurements.

Area of Science:

• Photonics and Materials Science
• Optical Sensing Technologies

Background:

• Development of advanced optical strain sensors is crucial for real-time structural health monitoring.
• Polymer-based optical devices offer advantages in flexibility and cost-effectiveness.

Purpose of the Study:

• To introduce a new optical strain sensor utilizing a polymer planar Bragg grating (PPBG).
• To characterize the sensor's performance under axial strain, focusing on wavelength shift and intensity response.

Main Methods:

• Fabrication of a PPBG sensor using bulk polymethylmethacrylate with a UV-inscribed optical waveguide and Bragg grating in a single step.
• Application of axial strain and measurement of the resulting Bragg wavelength shift and reflected intensity.

Main Results:

• The PPBG sensor demonstrated a quasi-instantaneous spectral red shift upon axial strain.
• A linear relationship was observed between the mechanical load and the Bragg wavelength shift.
• The sensor achieved a strain sensitivity of 2.95 pm/με.
• The relative reflected intensity remained constant within the tested load range.

Conclusions:

• The developed PPBG sensor is a promising tool for accurate and sensitive optical strain measurement.
• The single-step fabrication process offers a potentially streamlined manufacturing approach.
• The sensor's stable intensity response enhances its reliability for strain monitoring applications.