  We analyze the process of simultaneous photon pair generation and quantum
walks realized by spontaneous parametric down conversion of a pump beam in a
quadratic nonlinear waveguide array. We demonstrate that this flexible platform
allows for creating quantum states with different spatial correlations. In
particular, we predict that the output photon correlations can be switched from
photon bunching to antibunching controlled entirely classically by varying the
temperature of the array or the spatial profile of the pump beam.
