Correlation between ultraviolet-induced refractive index change and photoluminescence in Ge-doped fiber

The refractive index change arising following the UV exposure of a Ge-doped fiber was obtained by measuring the change in the far-field width of the fiber mode in the infrared. Simultaneous measurements showed a gradual decrease in the visible photoluminescence from the fiber which can be directly correlated to the photoinduced index change.