629Gbps Wavelength-Multiplexed 1 × 16 Programmable Visible Light Optical Switching for Data Center Optical Interconnects

The explosive growth of data traffic in the rapidly evolving intelligent era presents a significant challenge to information transmission within data centers (DCs). Visible light laser communication (VLLC) emerges as a promising optical interconnection solution due to its advantages of high capacity, low latency, and low energy consumption. However, existing VLLC-based optical interconnection architectures primarily rely on fixed, point-to-point links, lacking flexibility and programmability. To address this issue, this paper proposes and experimentally validates a flexible, high-capacity VLLC system enabled by programmable visible light optical switching. We introduce a Physics-inspired Forward-Backward Two-stage Network (PFBTNet) to achieve efficient optical field pre-manipulation in wavelength-division multiplexing (WDM) systems, enabling flexible and programmable visible light optical switching without additional post-processing. Experimental results demonstrate successful programmable WDM visible light switching ranging from 1 × 1 to 1 × 16 across a 4 × 4 receiver array, achieving a unicast switching efficiency of up to 0.99 and an average multicast efficiency exceeding 0.9. Furthermore, we experimentally demonstrate the average data transmission rates of 14.37 Gbps, 14.33 Gbps, and 10.63 Gbps for RGB 3-λ 16-channel optical interconnection by integrating external modulation and the bit-power-loading discrete multi-tone (DMT) modulation scheme. The maximum system throughput is projected to reach 629.28 Gbps, offering a promising solution for achieving flexible and ultra-high-speed VLLC-based optical interconnections in data centers.