Fig. 1. Scheme for the setup of FBG inscription via the beam scanning method.

Fig. 2. Reflectance and transmittance spectra of the identical FBGs.

Fig. 3. Wavelength evolution of the cascaded FBGs during the regeneration and temperature response.

Fig. 4. Reflective spectra of the cascaded FBGs during the regeneration and temperature response. The inset is the partial enlargement of the spectrum after the regeneration.

Fig. 5. Temperature dependence of the wavelength for the regenerated FBGs from 300°C to 900°C. The inset shows the method to obtain the Bragg wavelength of the cascaded FBGs.

Fig. 6. Wavelength evolution of regenerated FBGs under high-temperature strain.

Fig. 7. Reflective spectra of regenerated FBGs at 900°C under strain. (a) Starting and ending with the linear scale. (b) Process with the logarithmic scale.

Fig. 8. Time dependence of 10 dB bandwidth for the regenerated FBGs from 900°C to 1000°C and reflective spectra at 909°C and 1000°C.