1. A compute cluster comprising: a photonic interconnection having one or more branching optical transmission paths for transmitting independent frequency channels within an optical signal to each node in a set of nodes; one or more photonic-interconnection-based writers, each writer associated with a particular node and disposed adjacent to one of the branching optical transmission paths, each writer enodes information generated by the associated node into one of a first subset of the independent frequency channels that travel in the transmission paths in a first direction; a switch fabric that receives the first subset of independent frequency channels and encodes the information encoded in the first subset into a second subset of the independent frequency channels and sends the second subset on the transmission paths to the one or more nodes in a second direction, the second direction opposite the first direction; and one or more photonic-interconnection-based readers, each reader associated with a particular node and disposed adjacent to one of the branching optical transmission paths, each reader extracts the information encoded in one of the encoded independent frequency channels of the second subset directed to the associated node for processing.