QSFP-DD is a new module and cage/connector system similar to current QSFP, but with an additional row of contacts providing for an eight lane electrical interface. It is being developed by the QSFP-DD MSA as a key part of the industry's effort to enable high-speed. The Cisco ® family of QSFP-DD modules provide the industry's highest bandwidth density while leveraging the backward compatibility to lower-speed QSFP pluggable modules and cables. The Cisco 400GBASE Quad Small Form-Factor Pluggable Double Density (QSFP-DD) portfolio offers customers a wide variety. Quad Small Form-factor Pluggable Double Density (QSFP-DD) solution that fits into high-density switch and router client ports for optical interconnect links Powered by Greylock and Delphi DSP ASICs, and silicon photonic integrated circuits (PICs) for an optimized co-packaged design with 3D. The core difference between SFP and QSFP is lane count: SFP is a single-lane form factor (1G–25G), while QSFP aggregates 4 (or more) lanes to reach 40G, 100G, 200G and 400G (QSFP-DD). Choose by port density, target bandwidth, distance, and thermal budget. QSFP-DD connector portfolio's backwards compatibility allows. Supporting the continuing growth in the bandwidth demand and datacenter traffic driven by networking and AI/ML requirements, the QSFP-DD (Double Density) Interconnect System delivers 8 lanes with up to 28 Gbps NRZ or 56 Gbps-PAM4 (up to 400 Gbps aggregate) in a compact footprint that is backward. InnoLight 100G OpenZR+ QSFP-DD product family is designed based on dual polarization quadrature phase shift keying (DP-QPSK), supporting extended C-band, polarization diversity coherent detection and advanced electronic link equalization.