Reduction of DC drift in LiNbO/sub 3/ optical waveguide devices by ion exchange

The DC drift in Ti-diffused LiNbO/sub 3/ optical waveguide devices were remarkably reduced by adding an ion exchange process before the deposition of buffer layers in the device fabrication. The ion exchange was performed by heating the Ti-diffused LiNbO/sub 3/ substrate in molten alkaline metal nitrates. Lithium nitrate was found most effective.