Correlation of defect centers with photoinduced second-harmonic generation in Er- and Sm-doped aluminosilicate fibers

Abstract

The spectral dependence of photoinduced optical losses after chi((2)) writing have been obtained in Sm- and Er-doped fibers. The results show that Sm(2+) and Er(2+) can be a source of photoelectrons during fiber preparation.

Photoinduced refractive-index change in Sm^+2/Sm^+3 codoped aluminosilicate fiber by irradiation of an Ar-ion laser

“…Depending on the excitation wavelength and the host material, the electrons can be further excited to the conduction band of the host and then photoionized. This process has been suggested as a primary mechanism in persistent hole burning of Sm 12 ͞Sm 13 -doped glass 1 as well as second-harmonic generation 2 and is believed to play an important role in the photosensitivity of this f iber. The codoping of Sm 12 and Sm 13 ions in an aluminosilicate glass f iber was confirmed spectroscopically, and energy-level diagrams of the ions in the glass were suggested.…”

“…Photochemical hole burning of Sm 12 in various glass hosts at room temperature was reported 1 ; this hole burning was attributed to the photoionization of Sm 12 to Sm 13 . Recently, photoinduced second-harmonic generation was also observed in Sm-doped f ibers 2 ; the increase in the concentration of Sm 13 was the result of the photoionization of Sm 12 . Photosensitivity of a Eu 12 ͞Eu 31 -doped aluminosilicate fiber in the 4f 6 5d 1 ͑e g ͒ !…”