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

摘要

It is shown that long-period gratings can be written in a pure silica photonic crystal fiber without physical deformation by using the glass structure change. Long-period gratings with different grating periods are made by the glass structure change induced by arc discharge. We find that the resonance wavelengths decrease with increasing the grating period in contrast to long-period gratings fabricated in conventional fibers. This is due to large increase of the index difference between the pure silica core and the holey cladding against wavelength.