Multichannel and low-loss topological photonic crystal fiber in a mid-infrared band

A multichannel topological photonic crystal fiber (TPCF) with low loss is designed on the basis of two combined different basic photonic crystal units with topologically protected corner states. The relationship between the position modulation parameters and the characteristic frequency of the corner states is studied. Different spatial distributions of the corner states with different transmission wavelengths are found. Based on these corner states and the loss calculation, we designed a low-loss multichannel topological optical fiber. Fiber crosstalk has also been calculated. This low-loss multichannel fiber offers possibilities for applications in the mid-infrared range.