Abstract: An optical coupling device comprises a pair or connectors each receiving a bundle of optical fibers. Each connector is received in a housing which also receives an optical end of an optical mixing rod. A selected optical fiber of one of the bundles, when emissive, luminates the optical ends of all of the fibers in the other connector. The mixing rod has a central curved portion connecting rectilinear portions each of which is received in a respective one of the connectors. The arc of curvature of the curved portion of the mixing rod is such that light emitted by the emitting fibers is substantially equally distributed amongst the receiving fibers.