Chip-on-chip 3D optical interconnect with passive alignment

In this paper, a chip-on-chip 3D optical interconnect is introduced. The package consists of a SiOB and a flip chip mirror carrier. The light beam is deflected by two pairs of micro-mirrors on both the SiOB and the flip chip mirror carrier. The optical fibers are passively aligned with the pre-defined V-grooves on the SiOB. The mirror pairs on both the SiOB and the flip chip mirror carrier are self-aligned during the reflow of flip chip solder joints. The light is coupled form one optical fiber to another fiber through an "overpass" type of 3D optical path. The prototype shown in this paper is mainly for illustration purpose. In practice, the flip chip mirror carrier may be replaced by other devices such as VCSELs and photo detectors. The presented chip-on-chip 3D optical interconnects are suitable for coupling VCSELs or photo detectors with optical fibers. It is a low cost manufacturing process compared with the TO-can, which requires active alignment. Also, the potential capability to accommodate a small form factor laser array may be another major advantage of the proposed package.