Photon correlations in two-dimensional waveguide arrays and their classical estimate

Interference effects of photon pairs propagating through two-dimensional lattices of evanescently coupled waveguides are theoretically analyzed for input states of independent and path-entangled photons. Their correlation unveils characteristic Hong-Ou-Mandel interferences as well as more complex phenomena unique to these structures. Furthermore, purely classical states of light are used to simulate these quantum interferences in intensity correlation experiments. The results suggest that waveguide arrays can be employed as convenient devices for manipulating quantum states of light.