  We employ a cascaded system approach to numerically simulate the interaction
of photon pulses with a two-level scatterer in a chiral waveguide QED setup. It
is possible to expand any pure state of two photons as a superposition of
orthogonal two-photon pulses. We show that the scattering of a two-photon pulse
of suitable duration may lead to an entangled output state between
predominately two equally populated two-photon states. In a complementary wave
packet basis, this state is a product state of two orthogonal single photon
wave packets. The time reversal of the above scattering process allows for a
perfect combination of distinguishable single-photon wave packet into a
single-mode pulse carrying two identical photons.
