Three-dimensional wavelength-division multiplexing interconnects based on a low-loss Si x N y arrayed waveguide grating

Abstract

We fabricate three-dimensional wavelength-division multiplexing (3D-WDM) interconnects comprising three Si x N y layers using a CMOS-compatible process. In these interconnects, the optical signals are coupled directly to a Si x N y grating coupler in the middle Si x N y layer and demultiplexed by a 1 × 4 Si x N y array waveguide grating (AWG). The demultiplexed optical signals are interconnected from the middle Si x N y layer to the bottom and top Si x N y layers by four SiO x N y interlayer couplers. A low insertion loss and low crosstalk are achieved in the AWG. The coupling losses of the SiO x N y interlayer couplers and Si x N y grating coupler are ∼1.52 dB and ∼4.2 dB, respectively.