400G optical modules are mainly divided into CDFP, CFP8, QSFP-DD, and OSFP according to packaging methods. CDFP and CFP8 are larger in size and have higher thermal capacity and are mainly used in the telecommunications market.

QSFP-DD is forward compatible with the previous QSFP-28, with the smallest size and higher density. QSFP-DD is more suitable for use in short-distance data centers. QSFP-DD has many supporters including Facebook, Alibaba, Tencent and other companies.

Supporters of OSFP MSA include Google and Arista. The size of OSFP is slightly larger than that of QSFP-DD. The QSFP-28 optical module needs to add an adapter to be compatible with the OSFP socket. OSFP can support 800G backwards. OSFP comes with a heat sink and can support With 12w-15w thermal capacity, OSFP is more suitable for the telecommunications market.