A hybrid electro-optical data center system includes multiple tiers. A bottom tier has one or more bottom tier instances, with each bottom tier instance including one or more racks, an electro-optical switch corresponding to each rack, and a first bottom tier optical loop providing optical connectivity between the electro-optical switches of the respective bottom tier instance. At least one server within each rack is electrically connected to the respective electro-optical switch and at least one super-server within each rack is electrically and optically connected to the respective electro-optical switch. A top tier includes electro-optical switches, each electrically connected to an electro-optical switch in a respective bottom tier instance, a first top tier optical loop providing optical connectivity between the electro-optical switches of the top tier, and one or more optical add/drop modules providing optical connectivity between the first bottom tier optical loop and the first top tier optical loop.