Photosensitive, all-glass AgPO3/silicaphotonic bandgap fiber

Photonic bandgap (PBG) guidance is observed in a solid core photonic crystal fiber (PCF) consisting of silver metaphosphate (AgPO(3)) glass embedded into a silica cladding, realized by vacuum-assisted infiltration of the molten glass into the hollow channels of a commercial silica PCF. Morphologic analysis of the cladding microstructure by optical and scanning electron microscopy reveals the formation of highly homogeneous glass strands along the PCF length. The characteristic transmission spectrum of the fiber shows PBG guidance in the range between 350 and 1650 nm. The exposure of the cladding glass matrix, using 355 nm, 150 ps laser irradiation, allows photo-induced enhancement of the transmission-to-stop-band extinction ratio by ～60 dB/cm and bandwidth tuning. Numerical calculations of the transmission pattern of the fabricated AgPO(3)/silica bandgap fiber are in good agreement with experiments.