  Concatenated backward ray mapping is an alternative for ray tracing in 2D. It
is based on the phase-space description of an optical system. Phase space is
the set of position and direction coordinates of light rays intersecting a
surface. The original algorithm is limited to optical systems consisting of
only straight surfaces; we generalize it to accommodate curved surfaces. The
algorithm is applied to a standard optical system, the compound parabolic
concentrator. We compare the accuracy and speed of the generalized algorithm,
the original algorithm and Monte Carlo ray tracing. The results show that the
generalized algorithm outperforms both other methods.
