The 400G QSFP-DD Active Optical Cable integrates QSFP-DD transceiver interfaces and multimode fiber cable into one factory-terminated assembly. It is designed for high-speed short-reach connections such as switch-to-switch, switch-to-server and rack-to-rack links in high-density data center environments. Compared with separate optical modules and patch cords, the AOC solution simplifies installation, reduces cabling complexity and delivers reliable, low-latency 400G transmission for cloud computing, AI clusters and high-performance switching applications.