Enhanced high temperature properties of overexposed FBG fabricated by femtosecond laser

The high temperature properties of fiber Bragg gratings (FBGs) fabricated by overexposure using femtosecond laser phase mask technology are investigated. It is found that the overexposed FBG (FBG-II) has exhibited a temperature resistance of up to1000 degrees C and a reflection intensity of over 12 dB after air cooling treatment at 1000 degrees C for 5 h, as well as showing better high temperature stability than the unexposed gratings (FBG-I). Moreover, the temperature stability of FBG-II can be enhanced obviously through the rapid air cooling treatment after high temperature annealing, as well as the higher the air cooling rate, the more significant the effect. In addition, the wavelength hysteresis and spectral repeatability of the FBG-IIs can be significantly improved through the method. This research essentially provides a new approach to enhance the thermal properties of FBG and shows great potential in a harsh environment.

Automated summary

This research investigates the high temperature properties of fiber Bragg gratings (FBGs) fabricated by overexposure using femtosecond laser phase mask technology. The overexposed FBG (FBG-II) exhibits temperature resistance up to 1000 degrees C and a reflection intensity of over 12 dB after air cooling treatment. The temperature stability of FBG-II can be significantly enhanced through rapid air cooling treatment, with higher air cooling rates yielding more significant effects.