On-chip large-scale all-optical interconnect for ultra-low-latency deep neural network inference

As artificial intelligence (AI) models continue to expand rapidly and evolve at an accelerating pace, the sustainability of scaling law faces challenges as computational resources cannot expand indefinitely. A more promising strategy is to use high-performance interconnections to compose multiple modest-capacity computing chips into a high-efficiency system, enabling comparable capability to that of much larger resource-intensive systems. However, an effective on-chip communication and network that provides high bandwidth, low latency, and large-scale parallelism to accelerate distributed computation is still lacking. Here, we address this challenge by proposing an on-chip, all-optical-interconnect-based hybrid optoelectronic distributed computing system, achieving two orders of magnitude lower inference latency than a single graphics processing unit (GPU) while using only one-ninth of its computational resources. The 400-gigabits per second (Gbps) silicon photonic transceiver chips can provide high-speed and error-free optical input/output (I/O) for processing chips, and an ultra-low-loss (≤ 5 dB at 1300 nm), non-blocking 16×16 optical switch chip can further scale out the all-optical network for massive and flexible interconnection. As a validation, we configure the system to realize optical pipeline parallelism (OPP) and execute a five-layer convolutional neural network (CNN) denoising model, which processes a total of 1,000 images of 32,768 bits each in only 105.16 µs. These results convincingly illustrate a transformative pathway toward future high-efficiency computing architectures.