Optimising apodized grating couplers in a pure SOI platform to −05 dB coupling efficiency

• DOI: 10.1364/oe.23.016289
• Publication Date: 2015-06-11T21:05:33Z
• Authors: Angelo Bozzola; Lee Carroll; Dario Gerace; Ilaria Cristiani; Lucio Claudio And...
• Keywords: Apodization; Diffraction efficiency

We present a theoretical optimisation of 1D apodized grating couplers in "pure" Silicon-On-Insulator (SOI) architecture, i.e. without any bottom reflector element, by means general mutative method.We perform comprehensive 2D Finite Difference Time Domain study chirped and 220 nm SOI, demonstrate that the global maximum coupling efficiency platform is capped to 65% (-1.9 dB).Moving designs with thicker Si-layers, we identify new record design 340 simulated 89% (-0.5 dB).Going Si layers does not further improve efficiency, implying -0.5 dB may be for coupler SOI bottom-reflector.Even after allowing 193 UV-lithographic fabrication constraints, still offers -0.7 efficiency.These are first pure compatible deep-UV lithography offer better than -1 insertion losses.With only very minor changes existing deposition recipes, they multi-project wafer runs already offered Si-Photonics foundries.