Review Article
Gratings in Structured Optical Fibres
Figure 1
Typical structured optical fibres into which gratings have been
written: (a) low-loss (<4 dB/km) 4-ring all-silica photonic
crystal optical fibre; (b) 12-ring photonic crystal fibre with
triangular core and photosensitive, high-NA step-index
germanosilicate center; (c) simple Fresnel fibre; and (d) air-clad
fibre with Y-doped core.