A 3D-integrated 8λ × 32 Gbps λ Silicon Photonic Microring-based DWDM Transmitter

Silicon photonics-based optical 1/O is a promising technology direction to meet the ever growing off-chip 1/O bandwidth needs of data-intensive computing. While silicon photonic (SiPh) transceivers are increasingly being used in pluggable modules for data center communications, the power efficiency and latency constraints for their integration in XPU/switch packages (such as recent demonstrations in [1], [2]) are significantly more stringent, requiring different solutions. Ring resonator-based transceiver architectures are attractive for this application due to their small footprint and suitability for dense wavelength division multiplexing (DWDM), which enables energy-efficient bandwidth scaling. System demonstrations of ring-based transceivers with per-wavelength data rates of up to 16 Gb/s and low BER (<1e-12) have been shown recently [2]; however, these require an external multi-wavelength laser source, increasing optical path loss and requiring additional fibers be attached to the compute package. Prior demonstrations have shown higher baud rates in ring-based systems, but modulate only one wavelength at a time [3], [4]. This paper presents a SiPh microring-based TX that includes all photonic and electronic components needed to support simultaneous modulation of eight 200 GHz-spaced wavelengths at 32 Gbps/λ (for an aggregate bandwidth of 256 Gbps/fiber).