Integrated optical components on lithium niobate for optical communications

Besides active optical components such as lasers and photodiodes, passive and electro-optically controllable integrated optical waveguide structures play a fundamental role in the realization of optical communication networks. Lithium niobate is an advanced material for such components. The technology to fabricate low loss passive and electro-optically controllable waveguide structures in lithium niobate is easier and still more cost effective than in semiconductor materials. Even complex functions and fast switches are feasible today. After the development of suitable optical interfaces the realization of hybrid components including, e.g. lasers, photodiodes and fibre pigtails, may be an interesting alternative to the monolithic solution. Examples of components on lithium niobate such as polarization convertors, fast optical phase modulator, star couplers and switch matrices are described.