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

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