Hollow-core mode propagation in an isomeric nested anti-resonant fiber.

We present a modified fiber model based on the nested hollow core anti-resonant fiber that enables the stable transmission of the orbital-angular-momentum mode HE. By replacing a pair of nested anti-resonant tubes in the horizontal axis with resonant tubes, the coupling between core mode and cladding mode has been increased. Therefore, the relative strength of fundamental mode HE and the first higher mode HE has been modified. The numerical simulation results indicate that the loss ratio of the lowest loss HE to HE can be optimized to more than 187, while the HE still maintains a low confinement loss as 0.0027 dB/m. Our research has brought about a solution of low loss hollow core mode propagation in optical fiber. Those properties will make this fiber an ideal medium for blue-detuned atomic guidance.