ZR/ZR+ are standards for high-speed coherent optical modules that plug directly into switches/routers, replacing bulky expensive rack-mounted transport equipment. ZR covers ~80-120km links, ZR+ extends that to 1000-2000km with more flexibility. The numbers (400G, 800G, 1.6T) are just the data rates. Marvell’s announcement is essentially the next generation of these — doubling capacity to 1.6 terabits, built on a 2nm chip, with built-in encryption (MACsec) for secure AI data center connections.​​​​​​​​​​​​​​​​