Through-Silicon Photonic Via and Unidirectional Coupler for High-Speed Data Transmission in Optoelectronic Three-Dimensional LSI

We develop Si-core through-silicon photonic via (TSPV) and unidirectional coupler for low-loss and high-speed data transmission in an optoelectronic 3-D LSI. The TSPVs, comprising a Si-core and SiO₂ cladding, were fabricated simultaneously with Cu TSVs. The characteristics of light confinement of the TSPV were measured using a near-field pattern measurement. The spot light area was well confined within the TSPV without interference from the lights. The optical intensity that passed through the TSPV was 20% higher than that which passed through the Si substrate. The unidirectional optical coupler with two mirrors showed higher coupling efficiency. Laser light can be efficiently propagated to a planar Si waveguide through the TSPV and the unidirectional coupler.