1. A photonic cluster state generator, comprising an optical divider stage having an input into which photons from a photon source are applied, and a plurality of outputs among which said photons are evenly divided and output; a like plurality of polarization and delay stages for synchronizing said photons in time; a like plurality of first entanglement stages for creating entangled chains of said synchronized photons; a plurality of second entanglement stages for entangling said photon chains so as to produce and output cluster states; a controller for selectably controlling said delay and entanglement of said photons and photon chains; and a clock source for synchronizing said controller with the arrival of said photons.