A simple analytical model for confinement loss estimation in hollow-core Tube Lattice Fibers

Abstract

In this work, we propose an analytical model for estimating confinement loss in Tube Lattice Fibers. It is based on the single-tube model and the inhibited coupling waveguiding mechanism. The comparison with numerical simulations of tube lattice fibers having different geometrical parameters and dielectric refractive indexes demonstrates the model validity and effectiveness. Being based only on analytical closed formulas, it constitutes a useful tool for rapid estimation of TLF CL. It also gives a more in-depth insight into the TLF guiding mechanisms, confirming the inhibited coupling is an appropriate and effective model for such kind of fibers.

Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

“…The small shift of the loss peak from the integer values has also been noted in several past numerical studies [3,23]. A comprehensive encounter of the origin behind the shift is presented in Reference [23]. We note that the widths and lowest ℑ eff values are roughly the same across all transmission bands.…”

“…The loss peaks are shifted slightly from the integer values and placed at ≈ 0.1, while the lowest ℑ eff in the mth-order transmission band appears at ≈ − 0.5 indicated with dashed-vertical lines. The small shift of the loss peak from the integer values has also been noted in several past numerical studies [3,23]. A comprehensive encounter of the origin behind the shift is presented in Reference [23].…”

“…As F approaches a resonance, the index mismatch between the fundamental core mode and dielectric cladding modes decreases, while their spatial field overlap increases, resulting in strong coupling between them. This leads to large light leakage in the core and corresponding rise in the confinement loss [23,24].…”

Analytical Formulas for Dispersion and Effective Area in Hollow-Core Tube Lattice Fibers

“…Driven by this motivation and the opportunity to better understand the confinement mechanisms, several analytical models, based both on approximated models and on empirical approaches, have been proposed [23][24][25][26][27][28][29][30][31]. Most of them focus on the effective index (n e f f ) and are only able to give a good estimation in a limited range of wavelengths (only one transmission band) and geometrical parameters [26][27][28][29][30].…”

“…Most of them focus on the effective index (n e f f ) and are only able to give a good estimation in a limited range of wavelengths (only one transmission band) and geometrical parameters [26][27][28][29][30]. In this work, we extend an empirical model, originally proposed for confinement loss (CL) estimation of the FM in tube lattice fibers (TLFs), [24] to also model TLF dispersion properties (n e f f , group velocity dispersion GVD) and effective area A e f f . These parameters play a fundamental role in designing fibers for non-linear applications [32], such as pulse compression [33,34], super-continuum generation [35,36], four-wave mixing [37], and Raman lasers [21].…”