The Open Eye Consortium (Open Eye MSA) has released a specification for fully analog 53-Gbps per lane PAM4 transmission over single-mode fiber. The MSA members expect the specification will lead to development of 50G SFP, 100G DSFP, 100G SFP-DD, 200G QSFP, and 400G QSFP-DD and OSFP single-mode modules that are less expensive and complex than digital approaches that require DSPs.