| 摘要 |
PURPOSE:To provide an optical waveguide which has stable and low propagation loss, is easily produced with good reproducibility, is adequately used for optical devices and consists of a lithium niobate crystal obtd. by external diffusion of Li and the process for production of this optical waveguide. CONSTITUTION:(1) This optical waveguide consists of the lithium niobate crystal which has <=0.1dB/cm propagation loss of 0.633mum wavelength and is obtd. by external diffusion of the Li. (2) This process for production of the optical waveguide consisting of the lithium niobate crystal obtd. by external diffusion of the Li comprises subjecting the grown lithium niobate crystal pool to annealing, poling and slicing, then annealing the crystal again to adjust the proton quantity and to uniformalize the concn., and subjecting the crystal to lapping and poling to a specular surface then to a proton desorption treatment in a dry oxygen atmosphere at <=-70 deg.C dew point temp. |
