A broadband single-polarization single-mode hollow core anti-resonant optical fiber

An anti-resonant hollow core fiber with an ultra-wide bandwidth of single-polarization single-mode (SPSM) operation is realized and analyzed in this paper. Double-ring circular cladding structure is introduced to control the reflection area and suppress high-order modes for the proposed fiber. To achieve SPSM behavior, an epsilon negative (ENG) material is fully filled in the selected cladding tubes to manipulate the effective material absorption loss (EML). By changing the parameters of the proposed fiber, the wanted (X-polarized) and unwanted (Y-polarized and high order) modes yield large loss differences (LD), i.e., SPSM guidance. Extensive simulation results demonstrate that the fiber exhibits an extra-wide SPSM wavelength bandwidth (from 1450 nm to 1620 nm) in conditions of minimum LD > 100 dB/m.