This book deals with an all-glass photonic crystal fiber (AGPCF) and an all-glass photonic band gap fiber (AGPBF) structures in which air-holes are replaced by doped silica rods in the cladding region to reduce the various difficulties such as deformation of air-holes and emergence of additional holes encountered during the fabrication process. Also, deals with photonic crystal based devices like ring resonator, splitters, combiners and sensor applications.