Long-Period Gratings in Hollow Core Fibers by Pressure-Assisted Arc Discharge Technique

We report on the fabrication of long-period gratings (LPGs) in hollow-core air-silica photonic bandgap fibers by using the pressure-assisted electrode arc discharge (EAD) technique. The EAD procedure combined with pressure actuation inside fiber holes enables the modification of hole size and shape in both core and cladding region avoiding holes collapsing and thus acts as a useful tool to impress effective refractive index modulation leading to low loss gratings. Periodically repeated EAD treatments permit the fabrication of LPG-based devices in hollow core optical fibers enabling new functionalities hitherto not possible. Here, the experimental demonstration of LPG prototyping with different characteristics exhibiting attenuation bands with depth up to 12 dB are reported.