A wavelength multiplexer using cascaded three-dimensional vertical couplers

A four-channel wavelength multiplexer/demultiplexer for sparse wavelength division multiplexing was demonstrated using cascaded three-dimensional (3D) vertical couplers. 17 nm channel spacing with crosstalk less than 15 dB was achieved. Strong coupled vertical couplers were fabricated using wafer bonding to invert a conventionally processed epitaxial layer and bond to a new host substrate. This technology makes the fabrication of 3D photonic integrated circuits and the realization of multilevel optical interconnects possible. (C) 2000 American Institute of Physics. [S0003-6951(00)03303-9].