Femtosecond direct-writing of low-loss fibre Bragg gratings with arbitrary reflection and dispersion profiles

Fibre Bragg gratings (FBGs) are critical elements in optical telecommunications and optical fiber sensor systems and are employed extensively in different types of fibre lasers. The inscription of FBGs with femtosecond (fs) laser pulses is particularly interesting, as it not only enables direct inscription into virtually any kind of optical fibre, but also offers an unprecedented control over the reflection and dispersion profiles of those gratings. In this paper we report on a novel core-scanning technique for the fabrication of novel FBGs and discuss their application in ultrashort-pulsed fibre laser systems as well as distributed feedback (DFB) lasers. In addition, we also show their suitability for sensing applications in radioactive environments.