GIGALIGHT 400G QSFP-DD PLR4 optical transceiver module is used for long-distance interconnection of data centers, conforms to IEEE 802.3cu 100GBASE-LR1 Ethernet transmission protocol, and is also compatible with IEEE 802.3bs 400GBASE-DR4 Ethernet transmission protocol. This product uses 4 pairs of parallel single-mode optical fiber transmission, the center wavelength is 1310nm, the distance can reach up to 10km (FEC needs to be turned on), and it supports 400G to 4x 100G-LR1 branch interconnection.