A two-step proton-exchange process to produce waveguides and gratings
in lithium niobate is described. In both steps, mixtures of lithium be
nzoate and benzoic acid are used. The fabricated components are charac
terized at 0.633 and 0.422 mum. In particular, we observe that the lig
ht intensity diffracted into the air by the grating is approximately 0
.5% of that in the waveguide.