Analysis of Reflective Self-Organized Lightwave Network (R-SOLNET) for Z-Connections in 3-D Optical Circuits by the Finite-Difference Time-Domain Method

Reflective self-organized lightwave network (R-SOLNET) is a novel optical waveguide formation method that utilizes an attractive force induced between light beams in photo-induced refractive index increase materials, in which the refractive index increases as a result of write-beam exposure. R-SOLNET forms self-aligned optical couplings between optical devices, which tolerate the mutual positional misalignment, and it also forms optical waveguides in a free space. We propose R-SOLNET in 3-D optical circuits for board/chip-level optical interconnects to reduce the amount of effort that is required for optical device assembly and vertical optical waveguide formation. We predicted by the finite-difference time-domain method that an optical Z-connection of R-SOLNET would vertically connect two 2-μm-core optical waveguide films stacked with a 10-μm gap. A self-aligned vertical waveguide is formed even when misalignment exists between the films. A coupling efficiency of >;40% is achievable with 25% misalignment in waveguide core assembly.