Fabrication and characterization of arc-induced long period gratings in optical fibers with micro-channels

In this work, we report about the fabrication and characterization of long period gratings (LPG) in so-called side-hole fibers (SHF). They have a different number (one, two, and four) of micro-channels in the cladding region, developing along the longitudinal direction of the optical fiber. For the first time, LPG inscription was performed by electric discharge technique in these fibers, resulting in devices with good spectral features, i.e. deep and narrow attenuation bands. The gratings were characterized in terms of response to surrounding refractive index, temperature, and strain, demonstrating the effectiveness of the fabrication process. The final aim is to provide a flexible sensing platform for the development of micro-fluidic devices for different applications.