Members of the CWDM8 Multisource Agreement (MSA) have released a new technical specification for 400-Gbps optical links at distances up to 10 km over duplex single-mode fiber. The new specification represents the industry's first 400G at 10 km interface focused specifically on implementation in next-generation optical module form factors, such as QSFP-DD or OSFP, for high-density data center networking equipment, the group asserts.
The new 10 km reach specification is a companion for the technical specification covering 400-Gbps optical transmission at distances up to 2 km over duplex single-mode fiber that the CWDM8 MSA released in November (see "New CWDM8 MSA specifications cover 400 Gbps over 2 km").

According to the group, the 400G CWDM8 optical interfaces were developed to support an array of high-bandwidth networking applications in data center, campus, enterprise, and metropolitan area networks.
The CWDM8 MSA group was formed to address 400-Gbps applications using NRZ modulation on the optical end, while maintaining compatibility with 50-Gbps per lane electrical interfaces (see "CWDM8 MSA targets 400G at 2 km, 10 km via NRZ wavelengths"). The group, which announced its formation this past September, says it is now accepting new contributor member companies.