Guided modes in chiral fibers: erratum

Modal bifurcation in chiral multilayered fibers

“…The bifurcation of the positive and negative modes can be drastic in the same fiber. An impedance matching chiral step-profile fiber could only support the positive (negative) modes as guided modes [16][17][18]. A pure chiral Bragg fiber guides the positive (negative) modes by the total internal reflection and the negative (positive) modes by the effect of Bragg gap [18].…”

“…However, if the imaginary part of the positive wavenumber of the core k 1 nearly vanishes, only the LCP mode suffers the material absorption. As shown in [16,17], F 1 and F −1 are separately associated with k 1 and k −1 and represent the RCP field and LCP field, respectively, if β ≈ k 1 . Although, for any mode in the fibers discussed here, both F and F − contribute the modal field, the RCP mode and LCP mode should be mainly determined by F 1 and F −1 , respectively.…”

“…One such feature is the bifurcation of waveguide dispersion, which exists in various chiral waveguides. As for chiral step-profile fibers, the bifurcation happens on the modes with opposite azimuthal wavenumbers [6,7,16,17,20], and the bifurcated modes are found to be separately RCP and LCP under certain conditions. For instance, provided a weakly guiding condition is satisfied, all the modes are circularly polarized (CP) in the chiral step-profile fibers with a uniform impedance [16,17]; similar results for plus and minus unity azimuthal wavenumbers are given in [7].…”

“…A variety of efforts have been made by researchers to explore new features arising in waveguides composed of chiral media (e.g., [2] and references therein, and [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]). One such feature is the bifurcation of waveguide dispersion, which exists in various chiral waveguides.…”

“…However, the impedance matching is not always indispensable. The weakly guiding condition is generally sufficient to guarantee the fundamental modes to be CP, which are the only modes guided in a single-mode fiber and most likely to possess the uniform polarizations supported by the bulk core medium [16,17]. The bifurcation of RCP and LCP modes in chiral fibers is not only limited to the waveguide dispersion.…”