Monolithically Integrated Silicon Photonic Local Oscillator‐Free Homodyne Receiver

ABSTRACT The exponential growth of global data traffic driven by artificial intelligence and cloud computing necessitates cost‐efficient, ultrahigh‐capacity optical interconnects. Integrated photonic interconnect offers a promising solution but faces critical bottlenecks: integrated coherent receivers require local oscillator (LO) lasers, resulting in material incompatibility and cost challenges for monolithic integration, while integrated self‐coherent schemes fundamentally suffer from nonlinear distortions induced by the nonlinear beating process between signal inputs during optical‐to‐electrical mapping, which limits both capacity and spectral efficiency. Here, we present an integrated LO‐free homodyne detection scheme with superior linearity enabled by a micro‐ring filter. The Si 3 N 4 micro‐ring resonator effectively filters out the optical carrier for homodyne detection, saving the LO in coherent receivers and eliminating the second‐order nonlinear distortions commonly encountered in self‐coherent schemes. Our fabricated monolithically integrated silicon photonic receiver enables single‐polarization 600‐Gb/s 16‐ary quadrature amplitude modulated orthogonal frequency division multiplexing signal transmission over an 80‐km fiber, achieving a net 480‐Gb/s per polarization. This represents an 86% improvement over previous integrated self‐coherent detection records and matches that of state‐of‐the‐art integrated coherent systems. Multichannel validation across the C band further confirms the dense wavelength‐division multiplexing compatibility. This work provides an Optical communication, dense wavelength division multiplexing, direct detection, integrated photonic interconnects, silicon photonicsscalable and cost‐effective solution essential for future 1.6 Tb/s per lane optical interconnects.