Hydrogen loading for fiber grating writing with a femtosecond laser and a phase mask.
The threshold for the fabrication of fiber Bragg gratings with ultrafast 800-nm radiation and a phase mask was studied in SMF-28 and all-silica core fiber by use of 125-fs pulses. High-pressure molecular hydrogen loading (H2 loading) was observed to significantly lower the grating writing threshold in standard Ge-doped telecommunication fiber. No reduction was observed with all-silica core fiber. The index change appeared to be confined to the Ge-doped core region of the fiber. Gratings in H2-loaded SMF-28 had thermal annealing behavior similar to UV-induced gratings. Unlike UV-induced H2-loaded gratings, no absorption associated with Ge-OH defect formation was observed.
Smelser
Christopher W
CW
Communications Research Centre Canada, 3701 Carling Avenue, P.O. Box 11490, Station H, Ottawa, Ontario K2H 8S2, Canada. christopher.smelser@crc.ca
Mihailov
Stephen J
SJ
Grobnic
Dan
D