One-dimensional perfect-shuffle networks are extended to two-dimensional perfect-shuffle networks, and this extension is analyzed by means of the finite-state model. The routing algorithm presented is based on quaternary numbers for 4 × 4 switches, and its extension to k × k switches is briefly discussed. In order to take full advantage of the three-dimensional interconnection capability and two-dimensional space-bandwidth product of free-space optics, we map one-dimensional perfect-shuffle networks into two-dimensional perfect-shuffle networks, with both having 4 × 4 switching elements. Finally we compare the permutation capability of two-dimensional perfect-shuffle networks with one-dimensional perfect-shuffle networks.