InP-InGaAsP wafer-bonded vertically coupled X-crossing multiple channel optical add-drop multiplexer

A vertically coupled InP-InGaAsP crossed waveguide optical add-drop multiplexer has been realized through the use of wafer bonding. Designed for signals in the 1550-nm range, this novel device requires only a single epitaxial growth and illustrates the use of vertical optical interconnects for the three dimensional routing of optical signals. To our knowledge, it is also one of the first optical vertically coupled devices with no horizontally coupled counterpart.