Study on photodamage of In:Er:LiNbO3 crystal waveguide substrates

In:Er:LiNbO 3 crystals with fixed Er concentration of 1mol% and variable In concentration of 1mol%, 2mol% and 3mol% have been grown by the Czochralski method, and then was made into waveguide substrates. The directly observing facula method was employed to measure the photo-damage resistance ability of the substrates, and it is found that In(3mol%):Er:LiNbO 3 has the highest photo-damage resistance ability among these three substrates. The structure was determined by the infrared transmittance spectra and the UV absorption spectra. The mechanism that the photo-damage resistance ability of the substrates increases with the increase of the doped concentration of In was discussed via the structure of the crystal.