Planar waveguides in calcium barium niobate fabricated by MeV He ion implantation

A planar optical waveguide was formed in calcium barium niobate (CBN) crystal by 2.8-MeV He-ion implantation with a dose of 1.0×10 16 ions/cm 2 at room temperature. The prism-coupling method was used to take dark mode measurements at both 633 nm and 1539 nm. The refractive-index profile (n o and n e ) of the He-implanted CBN waveguide was analyzed with the reflectivity calculation method. The results show that the MeV He implantation results in a decrease in refractive index in barriers for both n o (4.1%) and n e (3.1%), but for n e there is an increase in the waveguide region. The intensity profile of the guide mode and waveguide loss were obtained by end-fire coupling.