  In this paper, we consider the Cycle Packing problem on unit disk graphs
defined as follows. Given a unit disk graph G with n vertices and an integer k,
the goal is to find a set of $k$ vertex-disjoint cycles of G if it exists. Our
algorithm runs in time $2^{O(\sqrt k)}n^{O(1)}$. This improves the $2^{O(\sqrt
k\log k)}n^{O(1)}$-time algorithm by Fomin et al. [SODA 2012, ICALP 2017].
Moreover, our algorithm is optimal assuming the exponential-time hypothesis.
