Vertical antiresonant reflecting optical waveguide coupler for three-dimensional optical interconnects: optimum design for large tolerance, high coupling efficiency, and short coupling length

A compact antiresonant-reflecting-optical-waveguide- (ARROW) type vertical coupler for three-dimensional optical interconnects was demonstrated. The c oupler consists of stacked ARROW's channeled by the stripe lateral confinem ent structure, and each waveguide is completely separated by a thin metal f ilm in the separation region. In the coupling region the intermediate cladd ing of a previous coupler was made of the same material as that of the firs t cladding or the core. However, pre had to overcome the problem that both the high coupling efficiency and the large fabrication tolerance cannot be achieved simultaneously. Thus we incorporated an intermediate cladding made of a material different from that of the core and the first cladding The r efractive index and the thickness of the intermediate cladding were optimal ly designed to achieve large fabrication tolerance and a short coupling len gth with a high coupling efficiency. The coupling length was reduced from 4 .1 to 0.8 mm, and a high coupling efficiency of 96% was experimentally demo nstrated. (C) 2000 Optical Society of America. OCIS codes: 230.3120, 230.73 80, 250.5300.