Some peculiarities of Ti in‐diffusion in lithium niobate

Abstract

The process of one-and two-dimensional Ti in-diffusion in lithium niobate, LiNbO 3 (LN), single crystals of <x> and <z> orientations at 950-1060°С in oxygen/water vapor medium had been studied. In the case of onedimensional diffusion, a flat diffusion front consisting of Ti solid solution in LN is formed. The process kinetics is described by Fick's equation for the case of a permanent source. In the case of two-dimensional Ti diffusion, the diffusion zone contour acquires the shape close to elliptical. The diffusion rate in the tangential direction is about an order of magnitude higher than in the normal direction. A model qualitatively describing such nontrivial character of the diffusion process is suggested. The model is based on: a) incongruent lithium evaporation out of LN at high temperatures; b) low thermodynamic activity of Li in LiTiO 3 -product of Ti interaction with LN. These factors produce a significant nonlinearity of the process, since a strong chemical bond between Li and Ti in this phase leads to a mutual increase in their diffusive mobility.

Integration of chalcogenide and titanium-diffused lithium-niobate waveguides

“…Rings with this design have underlying Tidiffused layers. We anticipate more round-trip loss with this design owing to surface roughness created by titanium diffusion [11][12]. The roughness is also captured in figure 2c and is confined to top 20nm of the post-diffusion height.…”

Optical Waveguides Fabricated via Femtosecond Direct Laser Writing: Processes, Materials, and Devices

“…Optical waveguides of different configurations can be fabricated by many existing methods, including metal-ion indiffusion, [9][10][11][12][13] ion/proton exchange, [14][15][16][17] epitaxial layer deposition (sputtering, molecular beam epitaxy, chemical vapor deposition, pulsed laser deposition, etc. ), [18,19] and ion-beam implantation/irradiation.…”