The photosensitivity of ytterbium-doped optical fibers with aluminophosphosilicate glass cores

The phenomenon of photoinduced refractive index change in active optical fibers with Al$_{2}$O$_{3}$/P$_{2}$O$_{5}$/Yb$_{2}$O$_{3}$/SiO$_{2}$ core composition has been observed under the action of UV laser radiation with 193-nm wavelength. It is established that hydrogen treatment of active fibers plays a key role in ensuring a radical (about two orders of magnitude) increase in their photosensitivity. It is shown that intrafiber Bragg gratings with reflection coefficients above 99% can be formed, which are promising mirror reflectors for fiber laser cavities.