SiN x bilayer grating coupler for photonic systems

We present an apodized bilayer low-temperature plasma enhanced chemical vapor deposition (PECVD) SiNx grating coupler for foundry-based, dual SiNx layer, photonic applications. The grating coupler was designed for TE polarization in the C-band (1530–1565 nm). It has a simulated fiber-to-chip efficiency of −2.28 dB (59.1%) and a −1 dB bandwidth of 57.7 nm. Its measured fiber-to-chip efficiency and −1 dB bandwidth were −2.56 dB (55.4%) and 46.9 nm respectively. It was fabricated in a state-of-the-art 300 mm CMOS foundry with 193 nm deep UV argon-fluoride (DUV ArF) excimer-laser immersion lithography.