Bragg grating fabrication in germanosilicate fibers by use of near-UV light: a new pathway for refractive-index changes.
Using 334-nm light, we demonstrate side writing of Bragg gratings with an index change of ~10(-4) in germanium-doped fibers. No hydrogen loading of the fibers was required. These gratings have the same temperature stability as gratings fabricated with 240-nm light. Our results suggest that photoionization is not needed for formation of gratings in Ge-doped glass. We observe an enhancement of the 334-nm photosensitivity in boron-codoped fibers and suggest that B facilitates a structural transformation of the glass.
Starodubov
D S
DS
Grubsky
V
V
Feinberg
J
J
Kobrin
B
B
Juma
S
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