I.T. Wellington

Direct ultraviolet writing of channel waveguides in congruent lithium niobate single crystals

We report the fabrication of optical channel waveguides in congruent lithium niobate single crystals by direct writing with continuous-wave ultraviolet frequency-doubled Ar+ laser radiation (244 nm). The properties and performance of such waveguides are investigated, and first results are presented.

Ultraviolet writing of channel waveguides in proton-exchanged LiNbO3

We report on a direct ultraviolet (UV) writing method for the fabrication of channel waveguides at 1.55 µm in LiNbO3 through UV irradiation of surface and buried planar waveguides made by annealed proton exchange and reverse proton exchange. A systematic study of the guidance properties as a function of the UV writing conditions is presented.

UV laser-induced ferroelectric domain structures investigated by piezoresponse force microscopy

Ferroelectric domains have been generated on the +z and the -z faces of congruent undoped lithium niobate (LiNbO3) single crystals by direct UV writing using a continuous wave (c.w.) frequency doubled argon ion laser (lambda=244 nm). The width of the domains was observed to depend on the intensity of the laser beam. Interestingly, also the contrast of the domains seen by piezoresponse force microscopy (PFM) was observed to increase with higher laser intensity. The contrast difference could be attributed to a difference of the depth of these surface domains as the depth sensitivity of the PFM is ~1 mum for LiNbO3.

Modelling of UV direct-write waveguides in single crystal lithium niobate

It has been shown that waveguide structures can be directly written into single crystal LiNbO/sub 3/ through the influence of a focussed c.w. laser source at a wavelength of 244 nm scanned across the surface.