We present the design of a metal grating coupler compatible with membrane photonic circuit platforms, consisting of a buried metal grating and a metal mirror. A nonapodized design provides a fiber-to-chip coupling efficiency at 1.55 μm up to 73%, whereas apodized designs show theoretical efficiencies as high as 89%, with a 3 dB bandwidth of 61 and 78 nm, respectively. An important advantage is that the coupling efficiency is independent from the underlying layer stack, enabling its use in diverse applications. For example, a thin buffer layer is required to achieve optical coupling for the heterogeneous integration of III–V and silicon photonics, whereas a thick buffer is of interest for thermal isolation between photonic membranes and CMOS circuits.
© 2014 Optical Society of America
Original Manuscript: March 4, 2014
Revised Manuscript: April 2, 2014
Manuscript Accepted: April 2, 2014
Published: April 30, 2014
V. Dolores-Calzadilla, D. Heiss, and M. Smit, "Highly efficient metal grating coupler for membrane-based integrated photonics," Opt. Lett. 39, 2786-2789 (2014)