Polarization-maintaining fiber composed of an elliptical ring core and two circular air holes

In this paper, a new polarization-maintaining fiber (PMF) composed of an elliptical ring core and two circular air holes is exploited. The PMF could support 10 guided modes with refractive index differences $\Delta {n_{{\rm eff}}}$Δneff of all the adjacent modes larger than ${{10}^{ - 4}}$10-4. Moreover, the optimum parameters of the PMF covering the entire $C + L$C+L band are obtained. Last, the chromatic dispersion $D$D of the designed elliptical ring core fiber, the confinement loss $\alpha $α, and the power fraction $\chi $χ of the two-air core are calculated. The calculation results show that $D$D, $\alpha $α, and $\chi $χ are compatible with traditional step-index fiber, and the designed elliptical ring core fiber is suitable for mode-division multiplexing and optical fiber sensors.