Performance Comparison between QSFP-DD and OSFP for 56G-PAM4 Applications

摘要

The two form factors, QSFP-DD (Quad Small Form-Factor Double Density Pluggable) and OSFP (Octal Small Form-Factor Pluggable) are co-existing in the industry in both standards as well as field applications. This paper provides the detailed comparative study which can serve as the general guidelines for system engineers to apply them in current and future designs. First, the two form factor fundamentals are presented in detail in the component level of connector, raw cable, and thermal. The passive copper cable assembly DAC SI performance are followed. End-to-end channels are constructed with the QSFP-DD and OSFP 26 AWG 3m DAC passive links. Then, COM is used to analyze the end-to-end link performance for 56G-PAM4 applications. Finally, lab measured data based on a 56G-PAM4 SerDes with all 8 lanes running at speed is discussed with and without crosstalk.