High-order nonreciprocal add-drop filter

Topological photonics have led to robust optical behavior of devices, which has alleviated the influence manufacturing defects and perturbations on device performance. Meanwhile, temporal coupled-mode theory (t-CMT) been developed applied widely. However, t-CMT cascaded coupled cavities (CCC) system its corresponding high-order filter yet be established. Here, CCC is established based existing t-CMT. By combining with topological waveguides, a versatile design scheme nonreciprocal add-drop (HONAF) proposed. The relationship between coupling effect transmission filtering performance HONAF analyzed quantitatively. Then, method improve efficiency quality factor given. proposed combination gyromagnetic photonic crystals decagonal Penrose-type quasicrystals. are numerically analyzed, verifies consistency theoretical prediction numerical simulation. can widely used in resonator waveguides their related systems. excellent also wavelength division multiplexing/demultiplexing