Co-optimizing grating couplers for hybrid integration of InP and SOI photonic platforms

Grating couplers are widely used optical interfaces in integrated photonics, especially on the Silicon-On-Insulator (SOI) platform. Their design has been optimized for coupling light between a Photonic Integrated Circuit (PIC) and a single-mode fiber, a µlens for free space transport, or even a second PIC in the same SOI platform. In this work, we co-design matching pairs of grating-couplers on distinct SOI and InP photonic platforms for optimized PIC-to-PIC coupling. By matching the scattering strengths of the two grating-couplers, we show that a PIC-to-PIC insertion loss of 3dB can be achieved. We also investigate how the design parameters impact the coupling efficiency and the bandwidth, ending up with a tolerance analysis. The proposed coupling approach between two different waveguide materials has prospective applications for the hybrid-integration of SOI and InP photonic platforms for communication technologies.

Keywords

Grating couplers , Optical interfaces , Integrated photonics , Silicon-On-Insulator (SOI)

Citation

Passoni, M., Floris, F., Hwang, H.Y., Zagaglia, L., Carroll, L., Andreani, L.C. and O’Brien, P., 2018. Co-optimizing grating couplers for hybrid integration of InP and SOI photonic platforms. AIP Advances, 8(9), 095109 (8pp). DOI:10.1063/1.5046164