Fabrication and characteristics of optical waveguides on LiNbO3

Among the tremendous problems involving integrated optics and/or integrated optoelectronics, in this paper we give mainly a short review and a brief description of fabrication and characterisation techniques of planar optical waveguides made on lithium niobate single crystals. We note that research on waveguide integrated optic devices and systems are nowadays in a rather advanced stage. In fact, several components have been realized and tested, promoting the evolution of coherent optical fibre communications and high-speed signal processing. However integrated optics is still in its youth because, although it is clear what functions it can succesfully perform, much investigation remains to be done especially about a thorough understanding of waveguide technology in order to optimize device and system performances.