  We demonstrate experimentally that long-range intensity correlation for light
propagating inside random photonic waveguides can be modified by changing the
shape of the waveguide. The functional form of spatial correlation is no longer
universal in the regime of diffusive transport and becomes shape-dependent due
to the non-local nature of wave propagation. The spatial dependence of the
correlation may be asymmetric for light incident from opposite ends of the
waveguide. This work opens the door to control non-local effects in mesoscopic
transport of waves by manipulating the geometry of random systems.
