Integrated optic tunable add-drop filters for WDM ring networks

This paper deals with two types of thermo-optically tunable add-drop filter s realized by means of different technologies: fiber-matched low-pressure c hemical vapor deposited (LPCVD)-grown SiO2 waveguides and plasma-enhanced c hemical vapor deposition (PECVD)-grown high-refractive-index-contrast SiON waveguides. Design and technology aspects are outlined. The device characte rizations, drawn from laboratory and field trial measurements, are reported . The description focuses on the device applications in a system context. I n particular, the usefulness of the components as the basic elements of an optical add-drop multiplexer node, suitable for a ring network, is shown. T he key component aspects are presented as strictly related to system requir ements and issues.