Fiber Bragg gratings inscribed in nanobore fibers

The nanobore fiber (NBF) is a promising nanoscale optofluidic platform due to its long nanochannel and unique optical properties. However, the applications of NBF are only based on its original fiber geometry without extra functionalities so far, compared with various telecom fiber devices, which may limit its wide applications. Here, the first demonstration of NBF-based fiber Bragg grating (FBG) is introduced by the femtosecond (fs) laser direct writing technique and the ultraviolet (UV) laser phase mask technique, respectively. Moreover, the FBG fabricated via the UV laser was optimized, achieving high reflectivity of 96.89% and preserving of the open nanochannel simultaneously. The NBF-based FBGs were characterized in terms of temperature variation and different liquid-infiltration, showing the high potential in nanofluidic applications.