  We propose and theoretically study a method for the stochastic realization of
arbitrary quantum channels on multimode single-photon qudits. In order for our
method to be undemanding in its implementation, we restrict our analysis to
linear-optical techniques, vacuum ancillary states and non-adaptive schemes,
but we allow for random switching between different optical networks. With our
method it is possible to deterministically implement random-unitary channels
and to stochastically implement general, non-unital channels. We provide an
expression for the optimal probability of success of our scheme and calculate
this quantity for specific examples like the qubit amplitude-damping channel.
The success probability is shown to be related to the entanglement properties
of the Choi-Jamiolkowski state isomorphic to the channel.
