A synchronous optical bus system for communication between computer system components is described. In one example, the optical bus system is used for communication between a memory controller and memory devices optically coupled to an optical interconnect. Optical bus interface units couple the components to the optical interconnect and are arranged on the optical interconnect in order that a sum of an optical path length from a controller component to each computer system component and from each computer system component to the controller component is the same for all the coupled computer system components. A synchronous protocol is used for communication between the components.