| 摘要 |
A method of improving device performance of optical devices formed in optical substrates is disclosed. The method requires that the optical substrate material be pre-annealed to form a surface layer with a known congruent composition before diffusing the waveguide material into the substrate. By pre-annealing all material, the diffusion rate of the waveguide material will remain relatively constant, regardless of the particular boule. The pre-annealing can be accomplished either by pre-equilibrating the lithium niobate in a vapor-phase equilibration crucible containing pre-reacted lithium niobate cullet with the desired composition, or pre-equilibrating the lithium niobate to the Li2O-rich phase boundary in a two-phase (LiNbO3, Li3NbO4) powder bed. |
