Beam splitter benefits from topological antichiral edge states

Beam splitters play a crucial role in a wide range of optic-al systems. A typical beam splitter consists of several transport channels, and an input beam from one chan-nel is split into multiple output beams coupled into oth-er channels. For traditional beam splitters, their trans-portation channels (either in free space or waveguides) are reciprocal, being sensitive to various perturbations caused by defects and obstacles.