Various embodiments of the present invention are directed to optical broadcast buses configured with shared optical interfaces for fan-in and fan-out of optical signals. In one aspect, an optical broadcast bus comprises a number of optical interfaces, a fan-in bus optically coupled to the number of optical interfaces, and a fan-out bus optically coupled to the number of optical interfaces. Each optical interface is configured to convert an electrical signal produced by the at least one node into an optical signal that is received and directed by the fan-in bus to the fan-out bus and broadcast by the fan-out bus to the number of optical interfaces. Each optical interface also converts the optical signal into an electrical signal that is sent to the electronically coupled at least one node for processing.