The SFP-DD version 1.1 specification introduces improvements to the mechanical components and electrical interface schemes of the high-speed, high-density SFP-DD, which consists of a module, a connection system, and a housing, and is capable of supporting optical modules up to 3.5W in an enterprise environment.
 
Meeting the technical requirements of a dual-density interface, the SFP-DD form factor ensures mechanical interoperability of modular components produced by different manufacturers. The SFP-DD features a two-channel electrical interface, each channel supporting up to 25 Gbps with NRZ or 56 Gbps via PAM4, enabling an aggregate bandwidth of 56 Gbps or 112 Gbps with excellent signal integrity.
 
Combining an SFP-DD server port and QSFP-DD switch ports can double the port density in network applications. The SFP-DD interface helps meet the need for higher levels of port density and scalability in next-generation servers. By increasing speed and density, the SFP-DD electrical interface extends the existing SFP pluggable form factor, an interface commonly used in data centers and other network platforms. One of the key aspects of the SFP-DD v1.1 specification is backward compatibility. The SFP-DD port is compatible with legacy SFP and SFP+ cables, active optical cables, and modules, as well as all new SFP-DD electrical interfaces.

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