A new and simple concept of tunable two-chip microcavities for filter applications in WDM systems

A new and simple two-chip concept for microcavities with application in dense wavelength-division-multiplexed systems as tunable optical filters is presented. The Fabry-Perot cavity is created without any costly distance holder or sacrificial layer by simply utilizing the stress of the dielectric Bragg-mirrors against the semiconductor substrate. Electrostatic tunability is achieved by making use of the high capacitance of the metallized cantilevers holding the actuable membrane.