Manipulation of topological beam splitter based on honeycomb photonic crystals

The intriguing discoveries of quantum spin Hall effect of electrons and its analogy in photon systems have renovated several concepts in condensed matter physics. Here we emulate topological edge states at microwave frequencies utilizing honeycomb photonic crystals with elliptical rods made of silicon material, and a novel topological beam splitter is implemented and analyzed. Robustness against perturbations provides the beam splitter with extremely strong transmission stability. Noticeably, suppressing the backward transmission of electromagnetic wave mitigates undesirable reflection interference. The numerical analysis results reveal that the splitting ratio obtained is in the range of 0.5–1.5 and the maximum transmittance value can reach up to 97% in this system. Besides, by appropriately adjusting the configuration parameters of photonic crystals, the location of operating frequency can be tuned to match different cases. The proposed structure has tremendous potential applications in the field of all-optical integrated circuits and will promote the practicability of photonic topological insulators in the communication domain