We report the fabrication of a 12-μm -thick periodically poled LiNbO<sub>3</sub> planar waveguide buried in LiTaO<sub>3</sub> by direct bonding of precision-polished surfaces. Frequency doubling of the 1064-nm output of a cw diode-pumped Nd:YAG laser was performed in a 5.5-mm-long device with a 6.50-μm -period grating at an elevated temperature of 174 °C. The resultant green second-harmonic output exhibited fundamental-spatial-mode characteristics at a 4.3%W<sup>-1</sup> conversion efficiency.
© 1999 Optical Society of America
(160.3730) Materials : Lithium niobate
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4360) Nonlinear optics : Nonlinear optics, devices
(230.7390) Optical devices : Waveguides, planar
C. B. E. Gawith, D. P. Shepherd, J. A. Abernethy, D. C. Hanna, G. W. Ross, and P. G. R. Smith, "Second-harmonic generation in a direct-bonded periodically poled LiNbO3 buried waveguide," Opt. Lett. 24, 481-483 (1999)