  Spatial states of single photons and spatially entangled photon pairs are
becoming an important resource in quantum communication. This additional degree
of freedom provides an almost unlimited information capacity, making the
development of high-quality sources of spatial entanglement a well-motivated
research direction. We report an experimental method for generation of photon
pairs in a maximally entangled spatial state. In contrast to existing
techniques the method does not require post-selection and allows one to use the
full photon flux from the nonlinear crystal, providing a tool for creating
high-brightness sources of pure spatially entangled photons. Such sources are a
prerequisite for emerging applications in free-space quantum communication.
