The implantation of He+ into LiNb03 for the modification of the refractive index and the use of this technique for the fabrication of optical waveguides are reviewed in this paper. The effects of the various fabrication process parameters on the properties of the optical waveguides are also discussed.
B. L. Weiss,
"Review Of He+ Implanted Optical Waveguides In LiNbO3", Proc. SPIE 0704, Integrated Optical Circuit Engineering IV, (10 March 1987); doi: 10.1117/12.937150; https://doi.org/10.1117/12.937150