Keep high-speed links stable across longer runs with a 400 GbE QSFP-DD LR4 optical transceiver designed for 1310 nm transmission and up to 10 km reach. This module suits infrastructure teams that need to connect aggregation layers, inter-building links, or distributed data center zones without stepping down from 400 GbE performance. The QSFP-DD form factor supports dense switch and router platforms where port efficiency matters, while LR4 optics are built for single-mode fiber deployments that demand distance without sacrificing throughput. Mellanox compatibility helps simplify qualification in environments built around NVIDIA networking hardware, and TAA compliance supports procurement requirements for public sector and regulated buyers. For teams comparing optics at this tier, the value is in the combination of reach, compatibility, and sourcing discipline. It is the right choice when short-reach modules are not enough and lower-speed alternatives would create bottlenecks. Use it to preserve bandwidth headroom on critical links while keeping the network design clean and predictable.