FUSED VERTICAL COUPLERS

A vertical directional coupler fabricated using wafer fusion is demons trated with a very short coupling length of 62 mu m. The optical propa gation loss introduced by the fused layer is investigated. An excess l oss of 1.1 dB/cm at 1.55 mu m was measured for waveguides which incorp orate a fused junction near the core region. Fused vertical couplers m ake it possible to realize three-dimensional waveguide structures and compact switching arrays and they solve some of the topology problems of large switch arrays. (C) 1998 American Institute of Physics.