标题：Optical planar waveguide in sodium-doped calcium barium niobate crystals by carbon ion implantation
作者：Jin-Hua Zhao;Xi-Feng Qin;Feng-Xiang Wang;Gang Fu;Hui-Lin Wang;Xue-Lin Wang
作者机构：School of Science, Shandong Jianzhu University, Jinan 250101, China;School of Science, Shandong Jianzhu University, Jinan 250101
来源：Nuclear Instruments and Methods in Physics Research, Section B. Beam Interactions with Materials and Atoms
关键词：Ion implantation;Optical waveguide;Na:CBN
摘要：There is great interest in niobate crystals which belong to the tetragonal tungsten bronze (TTB) families owing to their intriguing properties. As one representative of such crystals, CBN (calcium barium niobate) has attracted rapidly growing attention. Because it has a higher Curie temperature than SBN (strontium barium niobate), possesses outstanding ferroelectric and it possesses optical properties. In addition, doped with sodium, CBN will show a higher Curie temperature than pure CBN. We report on the fabrication and characterization of optical planar waveguide in x-cut sodium-doped calcium barium niobate crystal by using C ion implantation. The guided-mode properties at the wavelength of 633 and 1539 nm are investigated through prism-coupling measurements, respectively. By applying direct endface coupling arrangement, the near-field optical intensity distribution of waveguide modes is measured at 633 nm. For comparison, the modal profile of the same guided mode is also numerically calculated by the finite difference beam-propagation method via computer software BeamPROP. The transmission spectra of the waveguide before and after ion implantation treatments were investigated also. Our experiment results reveal that the waveguide could propagate light with transverse magnetic polarized direction only and it is assumed that the polarization selectivity of CBN crystal may responsible for this phenomenon.