Si-Photonics-Based Layer-to-Layer Coupler Toward 3D Optical Interconnection

Nobuhiko NISHIYAMA  JoonHyun KANG  Yuki KUNO  Kazuto ITOH  Yuki ATSUMI  Tomohiro AMEMIYA  Shigehisa ARAI  

IEICE TRANSACTIONS on Electronics   Vol.E101-C   No.7   pp.501-508
Publication Date: 2018/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E101.C.501
Type of Manuscript: INVITED PAPER (Special Section on Distinguished Papers in Photonics)
Si photonics,  3D optical interconnection,  layer-to-layer coupler,  grating,  

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To realize three-dimensional (3D) optical interconnection on large-scale integration (LSI) circuits, layer-to-layer couplers based on Si-photonics platform were reviewed. In terms of optical cross talk, more than 1 µm layer distance is required for 3D interconnection. To meet this requirement for the layer-to-layer optical coupler, we proposed two types of couplers: a pair of grating couplers with metal mirrors for multi-layer distance coupling and taper-type directional couplers for neighboring layer distance coupling. Both structures produced a high coupling efficiency with relatively compact (∼100 µm) device sizes with a complementary metal oxide semiconductor (CMOS) compatible fabrication process.