Tunable acousto-optical filters, multiplexers and lasers in LiNbO/sub 3/

By combining acousto-optical polarization converters and passive polarization splitters in various ways on a single (X-cut) LiNbO/sub 3/ substrate a whole family of tunable integrated optical WDM-devices has been developed. Among them are wavelength filters, wavelength-selective switches and add-drop multiplexers. They offer fast and broad tunability. Due to their unique multi-wavelength operation capability simplified architectures of optical cross-connects and add-drop nodes can be realized. By fabricating these devices in erbium-diffusion doped LiNbO/sub 3/ internal amplification can be added by optical pumping. Moreover, by optical feedback in a cavity even lasing can be achieved with a tunable emission wavelength. In this contribution, the current state-of-the-art of tunable, acousto-optical devices in LiNbO/sub 3/ is reviewed, illustrated by a number of selected examples.