Scalable 3D dense integration of photonics on bulk silicon

We experimentally show vertically stacked, multi-layer, low-temperature deposited photonics for integration on processed microelectronics. Waveguides, microrings, and crossings are fabricated out of 400°C PECVD Si3N4 and SiO2 in a two layer configuration. Waveguide losses of ~1 dB/cm in the L-band are demonstrated using standard processing and without post-deposition annealing, along with vertically separated intersections showing -0.04 ± 0.002 dB/cross. Finally 3D drop rings are shown with 25 GHz channels and 24 dB extinction ratio.