Photorefractive effect in a periodically poled Ti : LiNbO3 channel waveguide

Abstract

The shift of the quasi-phase-matched wavelength and the degradation of the second harmonic power due to photorefractive damage ('optical damage') were investigated quantitatively as functions of the sample temperature and the coupled fundamental power in a Ti-diffused periodically poled LiNbO3 channel waveguide. The all-optical wavelength conversion was successively demonstrated by using the cascaded difference frequency generation process in a 76-mm Ti-diffused periodically poled LiNbO3 channel waveguide at an operating temperature of 192 degreesC. At that temperature, we observed no significant degradation of the second harmonic power and a very small shift of the quasi-phase-matched wavelength. The wavelength conversion efficiency was measured to be -8 dB, and the signal-to-noise ratio of the idler -35 dB.