Title :
Photorefractive effect in annealed proton-exchanged LiTaO/sub 3/ waveguides
Author :
Fujiwara, T. ; Cao, X.F. ; Ramaswamy, R.V.
Abstract :
Quantitative measurements of the photorefractive effect in annealed proton-exchanged (APE) LiTaO/sub 3/ waveguides have been measured for the first time. In particular, photorefractive measurements at 488 nm in waveguides fabricated on both surface acoustic wave (SAW) grade and optical grade LiTaO/sub 3/ substrates are reported and compared with that in optical grade APE LiNbO/sub 3/. The results show that while the dark conductivity and the saturated refractive index change of both APE LiTaO/sub 3/, samples remain the same at very high irradiation levels, the photoconductivity of the SAW grade is much higher than that of the optical grade. The large photorefractive charge may be due primarily to increased absorption by Fe/sup 2+/ impurity ions. Furthermore, as expected, optical grade APE LiTaO/sub 3/ exhibits a smaller photorefractive effect than that of LiNbO/sub 3/ at high intensities.<>
Keywords :
integrated optics; ion exchange; lithium compounds; optical waveguides; photoconductivity; photorefractive effect; refractive index; surface acoustic wave devices; 488 nm; Fe/sup 2+/ impurity ions; LiNbO/sub 3/; LiTaO/sub 3/; annealed proton-exchanged waveguides; dark conductivity; high intensities; high irradiation levels; increased absorption; large photorefractive charge; optical grade; photoconductivity; photorefractive effect; saturated refractive index change; surface acoustic wave; Acoustic measurements; Acoustic waveguides; Annealing; Optical refraction; Optical saturation; Optical variables control; Optical waveguides; Photorefractive effect; Surface acoustic waves; Time measurement;
Journal_Title :
Photonics Technology Letters, IEEE
