The trend for short-reach optical fiber communications, those used for data centers and HPC, has been to use simple and power-efficient approaches to scale bandwidth. Approaches include parallel single mode (ex. more fibers), multi-level modulation coupled with direct detection (ex. four-level pulse amplitude modulation or PAM-4), and wide channel spacing (i.e. coarse WDM or CWDM). Bandwidth and computing demand is increasing at an unprecedented rate, and power consumption cannot practically scale at this same rate. We propose to avoid or limit complex and power-hungry concepts such as dense WDM (DWDM), optical phase-locked loop (OPLL) based coherent detection, narrow channel spacing, and high Baud rate, and instead leverage an untapped approach to minimize energy consumption, namely Multi core fiber (MCF)-based Space Division Multiplexing (SDM). To further the development of energy efficient integrated photonic networking technologies for datacenters and high performance computing (HPC), we propose to revolutionize chip-to-chip interconnects with massively parallel photonic channels based on photonic integrated circuit (PIC) technology and spatial division multiplexing (SDM).Enabling this approach is the world record ultra-low loss Silicon Photonics (SiPh)-compatible silicon nitride (SiN) waveguide technology developed by Ultra-low Loss Technologies (ULL). ULLs ultra-low loss SiN technology achieves between 10-1000X reduction in loss compared to competing technologies, and this translates directly into lower power consumption.
