  We explore a hexagonal cavity that supports chiral topological whispering
gallery (CTWG) modes, formed by a gyromagnetic photonic crystal. This mode is a
special type of topologically protected optical mode that can propagate in
photonic crystals with chiral direction. Finite element method simulations show
that discrete edge states exist in the topological band gap due to the coupling
of chiral edge states and WG modes. Since the cavity only supports edge state
modes with group velocity in only one direction, it can purely generate
traveling modes and be immune to interference modes. In addition, we introduced
defects and disorder to test the robustness of the cavity, demonstrating that
the CTWG modes can be effectively maintained under all types of perturbations.
Our topological cavity platform offers useful prototype of robust topological
photonic devices. The existence of this mode can have important implications
for the design and application of optical devices.

Optics;Mesoscale and Nanoscale Physics