Optically coupled multi-node computing system

An apparatus includes a plurality of nodes coupled to an optical network, each node including an optical transmitter interface configured to transmit an optical signal at a location along a coupled optical path of the optical network and an optical receiver interface configured to receive the optical signal at a location along the coupled optical path of the optical network. The apparatus includes a first optical path configured to propagate the guided-mode optical network around a closed path and a second optical path configured to propagate the guided-mode optical network around the closed path. The first optical path and the second optical path overlap each other at a first set of four positions, the first optical path being coupled to two or more of the nodes at a second set of respective positions different from the positions of the first set of positions, and the second optical path is coupled to two or more of the nodes at a third set of respective positions different from all of the first set of posit