  Topological corner state (TCS) and topological edge state (TES) have provided
new approaches to control the propagation of light. The construction of
topological coupled cavity-waveguide system (TCCWS) based on TCS and TES is
worth looking forward to, due to its research prospects in realizing
high-performance micro-nano integrated photonic devices. In this Letter, TCCWS
is proposed in two-dimensional (2D) photonic crystal (PC), which possesses
strong optical localization, high quality factor and excellent robustness
compared with the conventional coupled cavity-waveguide system (CCCWS). This
work will provide the possibility to design high-performance logic gates,
lasers, filters and other micro-nano integrated photonics devices and expand
their applications.
