The Open Eye Consortium (Open Eye MSA) published its 53 Gbps single-mode specification defining the requirements for analog PAM-4 solutions for 50G SFP, 100G DSFP, 200G QSFP, and 400G QSFP-DD and OSFP single-mode modules.
The Open Eye MSA aims to accelerate the adoption of PAM-4 optical interconnects scaling to 50Gbps, 100Gbps, 200Gbps, and 400Gbps by expanding upon existing standards to enable optical module implementations using less complex, lower cost, lower power, and optimized analog clock and data recovery (CDR) based architectures in addition to existing digital signal processing (DSP) architectures.
A whitepaper is available to view and download.
In addition, the Open Eye MSA announced the draft of its multi-mode specification available to its members for comments, with general availability targeted for release in Fall 2020.
http://www.openeye-msa.org