Concentration and refractive index profiles of titanium- and iron-diffused planar LiNbO3 waveguides

Abstract

Depth profiles of titanium, iron, and niobium concentrations are investigated with an electron microprobe in planar optical LiNbO3:Ti waveguides additionally doped with iron. The profiles are well described by Gaussian functions allowing the determination of diffusion constants. The extraordinary refractive index of the waveguides can be described by a linear superposition of iron and titanium profiles.

Anisotropic two- and four-wave mixing in planar LiTaO_3:Ti:Fe optical waveguides

“…The linear dependence of refractive-index changes Anle and Ano on titanium concentration in LiTaO 3 is verified by microprobe investigations, as described in Ref. 16.…”

“…Ejj~~y~ex L -2estj (16) where e.tat = e 22 9tat is the static dielectric constant and Eerase is the electric field of the erasing mode. The decay of the grating is measured by means of the decrease of diffraction efficiency, which is defined as the ratio of diffracted and total light intensity: Here d is the interaction length and Eread is the electric field of the mode that reads the hologram.…”

Holographic Measurement of Dark Conductivity in LiNbO3:Ti:Fe Planar Optical Waveguides

“…For the different modes of a waveguide, i.e., for different propagation depths, we obtain almost the same dark conductivity. This is expected from the nearly constant iron concentration in the waveguiding layer, and points to a minor influence of titanium on dark conductivity, because the titanium concentration strongly decreases with increasing propagation depth [6].…”

“…2 , with penetration depths r Ti 3X6 mm and r Fe 10X7 mm, respectively [6]. All waveguides are multimode with typical depths of the nearly Gaussian refractive index profiles of r wg % 5 mm.…”

Photorefractive Waveguides

“…For application of the photorefractive effect, waveguides fabricated by combined titanium and iron or copper diffusion, respectively, have shown considerably improved holographic sensitivity [34,35].…”