Monday, February 18, 2019

Gigalight: QSFP-DD might be the mainstream form-factor for 400G

Optical transceiver manufacturers are recognizing the Quad Small Form Factor Pluggable Double Density (QSFP-DD) as the mainstream form factor for 400G optical modules, according to Gigalight, athough some manufacturers have also introduced 400G optical modules with OSFP and CFP8 form-factors.

The QSFP-DD form factor expands the standard QSFP four-lane interface by adding a row of contacts providing for an eight-lane electrical interface, each operating up to 25 Gbps with Non-Return-to-Zero (NRZ) modulation or 50 Gbps with Pulse Amplitude Modulation (PAM4). This adaptation allows the QSFP-DD form factor to address solutions up to 400 Gbps aggregate per QSFP-DD port, while providing backward compatibility to 40 Gbps and 100 Gbps.

This Gigalight paper traces the work of the QSFP-DD MSA group since its inception two years ago in March 2016, features and benefits, as well as marketplace progress.