Design of the novel steering-wheel micro-structured optical fibers sensor based on evanescent wave of terahertz wave band

In this paper, we present design of a hollow micro-structured photonic crystal fiber with novel steering-wheel pattern of noncircular large holes in cladding as platform for evanescent-field sensing. Based on simulation, confinement loss is less than 0.007 dB/m, and 72% of light intensity overlaps in noncircular large air holes is obtained when the incident wave frequency is 1 THz, and the nonlinear effects of the short-distance transmission are very small simultaneously. The critical value of confinement losses increases with the structure parameters. As for ultra-low loss and high sensitivity of the model, the novel steering-wheel structured fiber is well suited for evanescent-field sensing and detection of chemical and biological products.