  Coherence distillation is a central topic of the resource theory of coherence
and various coherence distillation protocols were proposed. In this paper, we
investigate the optimal probabilistic coherence distillation protocol, whose
aim is to transform a coherent state into a set of $n$-level maximally coherent
states by using strictly incoherent operations. Specifically, we accomplish
this protocol by presenting an analytical expression for the maximal average
distillable coherence for a general state and constructing the corresponding
operation achieving this bound. Our protocol is a universal protocol since it
can be applied to any coherence measure.
