Anti-Resonant Hollow Core Fibers with Modified Shape of the Core for the Better Optical Performance in the Visible Spectral Region—A Numerical Study

Abstract

In this paper, we present numerical studies of several different structures of anti-resonant, hollow core optical fibers. The cladding of these fibers is based on the Kagomé lattice concept, with some of the core-surrounding lattice cells removed. This modification, by creating additional, glass-free regions around the core, results in a significant improvement of some important optical fiber parameters, such as confinement loss (CL), bending loss (BL), and dispersion parameter (D). According to the conducted simulations (with fused silica glass being the structure’s material), CL were reduced from ~0.36 dB/m to ~0.16 dB/m (at 760 nm wavelength) in case of the structure with removed cells, and did not exceed the value of 1 dB/m across the 700–850 nm wavelength range. Additionally, proposed structure exhibits a remarkably low value of D—from 1.5 to 2.5 ps/(nm × km) at the 700–800 nm wavelength range, while the BL were estimated to be below 0.25 dB/m for bending radius of ~1.5 cm. CL and D were simulated, additionally, for structures made of acrylic glass polymethylmethacrylate, (PMMA), with similarly good results—DPMMA ∊ [2, 4] ps/(nm × km) and CLPMMA ≈ 0.13 dB/m (down from 0.41 dB/m), for the same spectral regions (700–800 nm bandwidth for D, and 760 nm wavelength for CL).

Understanding Dispersion of Revolver-Type Anti-Resonant Hollow Core Fibers

“…It is important to note that already the most generic type of ARHCF geometry-the tube-type fiber (TTF, Figure 2) geometry-qualitatively shows all key features of an ARHCF, namely strong resonances imposed by the ARE-modes and a characteristic loss evolution within the transmission bands. This approximation was utilized by several authors [27][28][29][30] to simulate complex ARHCF structures on the basis of the properties of the TTF geometry. Recent experiments involving improved designs of RTFs indicate that these types of fibers show off-resonance losses as low as 7.7 dB/km within various spectral domains [31], making it highly attractive for numerous applications.…”

A Dual Hollow Core Antiresonant Optical Fiber Coupler Based on a Highly Birefringent Structure-Numerical Design and Analysis

“…These mode profiles are presented in the inserts of Figure 2b, and one can see that the field amplitudes in the vicinity of the walls of external capillaries are higher for structure-X. To ensure this observation, the total power fraction confined in the glass components of the designed DHC-ARF, η, was calculated according to the following formula [37]:…”

“…These fibers are known for their multiple, wide transmission windows and remarkably high core-mode confinement, which reduces their dispersion to only a few ps/nm × km. All of the above, combined with a great modification and design flexibility of HC-ARFs, have resulted in researchers presenting numerous different structures based on two most known HC-ARF cladding types-the single-ring [34,35] and Kagomé [36,37] types. This flexibility can also be considered one of the factors which have encouraged researchers to pursue the idea of a dual hollow-core antiresonant fiber (DHC-ARF).…”

Selective and Colorimetric Detection of p-Nitrophenol Based on Inverse Opal Polymeric Photonic Crystals

“…Photonic crystals, consisting of periodic arrangements of dielectric materials with different refractive indexes, produce color when the photonic stop bands are located in the visible range [9][10][11][12][13][14][15][16][17][18]. Because the response process of photonic crystals can be directly expressed by light diffraction signals (the structure color "naked eye" can be seen) without any marking technology or any other analytical instruments, much attention has been paid to it in the field of sensor design and application [19][20][21][22][23][24][25][26][27][28][29][30][31].…”