6T optical modules differ primarily in bandwidth, power efficiency, and deployment scenarios. However, 400G remains more cost-effective for. This is achieved through hardware upgrades, including more advanced switches, routers, and servers, which offer higher bandwidth via increased port speeds and higher port counts relative to previous generations. In parallel, the optical interconnects that link these network devices must also scale. Optical modules, which serve as the building blocks for optical communication systems, are at the forefront of this evolution. This article will explore the evolution of modules' speed and form factor from 400G to 1.