This Multi-Source Agreement (MSA) defines 4 x 100 Gbps Coarse Wavelength Division Multiplex (CWDM) optical interface for 400 Gbps optical transceivers for Ethernet applications. Forward error correction (FEC) is required to be implemented by the host in order to ensure reliable system operation. Two transceivers communicate over single mode fibers (SMF) of length from 2 meters to at least 2 kilometers. The transceiver electrical interface is not specified by this MSA but can have, for example, eight lanes in each direction with a nominal signaling rate of 53.125 Gbps per lane or four lanes in each direction with a nominal signaling rate of 106.25 Gbps per lane.
A variety of form factors for the 400G-FR4 transceivers are possible and none are precluded by this MSA.