The 400G-FR4-LPO specification provided in this document is optimized for data-center specific needs and broadly maintains interoperability with standard 100G per lane DSP based LR SerDes. 125 GBd, PAM4 optical interface using standard single-mode fiber with reach up to at least 500 m, and host-module electrical interfaces for hosts with DSP based SerDes and RS(544,514). Broadcom's Optical Module PHY portfolio spans multiple technology nodes — 16nm, 7nm and now 5nm, with data rates from 100 Gbs to 1. Comprising five flagship platforms, Centenario, Jesko, Portofino, Gemera, and Cygnus, Broadcom's DSP PAM-4 portfolio covers 100G, 400G, 800G, and 1. 6T PMDs. Last year, module vendors demonstrated the first 1. 6T modules connect a 16x100G host interface to 8x200G optics (16:8), next-generation designs will work with forthcoming. Continuing our discussion on 100G optical modules, let's explore the essential 100G transmission standards—SR4, DR1, DR4, BiDi SR, LR4, CWDM4, SWDM4, ER, and ZR. These standards often cause confusion when selecting the right module for your needs. The Marvell® PAM4 optical DSP portfolio, including Spica™ and Nova™ DSPs, addresses the critical the need for high-bandwidth optical interconnects to power AI infrastructure. Marvell leads the pluggable module ecosystem with low-power, high-performance silicon for AI, cloud, enterprise and 5G.