A planar waveguide composed of the new nonlinear material, Ca<sub>4</sub>GdO(BO<sub>3</sub>)<sub>3</sub> (GdCOB), is reported. This crystal belongs to the calcium oxoborate family. It has attractive nonlinear properties that can be of great interest in integrated optics applications. We used a method of He<sup>+</sup> implantation to fabricate waveguides in GdCOB crystals by creating a buried layer of lowered refractive index a few micrometers beneath the surface. Both TE and TM modes were observed. Therefore, according to the Y cut of the crystal, refractive-index values of <i>n</i><sub>x</sub> , <i>n</i><sub>y</sub> , and <i>n</i><sub>z</sub> were obtained. Index profiles were reconstructed by an improved inverse WKB method. The profiles showed a steplike index behavior, indicating that the guiding region obtained was of good optical quality.
© 1998 America
A. Boudrioua, P. Moretti, G. Aka, and J. C. Loulergue, "Formation of planar optical waveguides in the new nonlinear gadolinium calcium oxoborate, Ca4GdO(BO3)3, crystal by 2-MeV He+ implantation," Opt. Lett. 23, 1680-1682 (1998)