Efficient metal grating coupler for membrane-based integrated photonics

Abstract

This paper reports the progress on the fabrication process of highly efficient metal grating couplers for membrane-based integrated circuits, using double side processing technology on bonded samples. This type of gratings comprises a buried SiO 2 /Ag grating of 125nm thickness with a silver layer as metal mirror, and has several advantages over dielectric gratings as metallic gratings are independent from the buffer thickness. We predict a theoretical chip-to-fiber coupling efficiency of 74% and 89% for uniform and apodized gratings respectively, at a wavelength of 1550 nm. Furthermore, the fabrication process can be used for both, SOI and III-V based platforms.

Waveguide-coupled metal-clad cavity with integrated feedback stub

“…In addition, achieving low-resistance electrical contact is also a nontrivial issue for such an ultra-small laser integrated on a narrow waveguide. While the previously-demonstrated isolated lasers usually employ large-area electrical contact on the bottom InP substrate for electrical pumping, 23,24) such configuration is not possible when integrating the cavity on a narrow silicon-on-insulator (SOI) waveguide. The top surface of the SOI waveguide would be the only available region to place the p-contact, which raises significant challenge in device fabrication.…”