A polarization maintaining optical fiber Bragg grating multi-parameter sensor

A polarization maintaining optical fiber Bragg grating (PMFBG) sensor with multi-parameter monitoring functions for composite structure has been studied theoretically and experimentally. A single embedded PMFBG is used as the sensor head for multi-parameter real-time monitoring in glass fiber reinforced polymer (GFRP) laminates. The temperature and stress response characteristics of the PMFBG in GFRP have been studied. The two peak wavelengths in the reflection spectrum of the PMFBG shift linearly with the temperature and/or stress of the laminates. Furthermore, the temperature sensitivity of the peak wavelengths of the PMFBG improve from 10.2m/degrees C to 17.8pm/degrees C ( x-axis) and from 9. 6 pm/degrees C to 15.1 pm/degrees C ( y-axis) after embedded in the composite laminates. The axial stress and temperature of the GFRP can be interrogated according to the two different wavelength shifts of the two peaks in the reflection spectrum. According to the experimental results, a single PMFBG sensor is competent for temperature and stress real-time monitoring simultaneously for composite structure.