Long-Period Gratings Written in a Pure Silica Photonic Crystal Fiber by the Glass Structure Change

摘要

Long-period gratings are written in a pure silica photonic crystal fiber without physical deformation using the glass structure change. The glass structure change is a simple and widely applicable method to modify refractive index locally in various glass fibers. A small part of a glass fiber is heated over its melt temperature by arc discharge, then the molten fiber undergoes rapid cooling, which freezes the change of the glass structure. Long-period gratings are made changing the grating period. The resonance wavelengths decrease with increasing the grating period in contrast to long-period gratings fabricated in conventional fibers.