A Negative-Curvature Hollow-Core Fiber Structure With Double Trigonal-Symmetrical Anti-Resonant Elements

Abstract

We propose a novel negative-curvature hollow-core fiber structure with double trigonal-symmetrical anti-resonant elements implementing single-mode or polarization-maintaining transmission for high-power laser delivery in the 1 µm wavelength window. For the single-mode fiber, the single-mode performance with a higher-order modes extinction ratio (HOMER) as high as 4.65 * 10 4 is achieved, and it remains >1 * 10 4 with a large fault tolerance proportion of tubes size, which can increase the flexibility of fiber fabrication. For another polarization-maintaining fiber, an ultra-low confinement loss of 0.005 dB/m is obtained for polarization-maintaining transmission by optimizing the refractive index of the two transverse glass tubes, while the polarization extinction ratio and HOMER remain both >1 * 10 3 . This is the first birefringent negative-curvature hollow-core fiber with a loss below 0.01 dB/m in the 1 µm wavelength window.

Highly Birefringent Low Loss NestedHollow Core Anti-resonant Fiber With A Silicon Layer

“…In this context, we compare the performance of our proposed AR-HCF with recently developed analogous structures, focusing on parameters such as birefringence, CL, bandwidth of birefringence, bending loss, and effectively single-mode operation (HOMER) as outlined in Table 1. This comparative analysis demonstrates that our proposed ber exhibits birefringence nearly an order of magnitude higher and CL one to two orders lower compared to recently proposed related structures [11,22,24,[26][27][28][29]. While only a few studies have discussed bending loss and single-mode characteristics, our ber showcases excellent performance in these aspects as well.…”

“…As a result, it is anticipated that a considerable wavelength span of 58 nm, ranging from 1539 nm to 1597 nm, will exhibit remarkable birefringence properties for the proposed AR-HCF. Within this wavelength span, the achieved level of birefringence represents a notable enhancement compared to recent structures proposed for AR-HCFs [11,[21][22][23][24][26][27][28][29].The augmentation of birefringence in the suggested structure is achieved through the strategic use of varying cladding wall thicknesses and the incorporation of high-index layers, such as silicon, along the x-axis. This introduces structural asymmetry, leading to varying degrees of light interaction for both x and y polarized cases.…”

“…Due to the inclusion of silicon layers along the x axis, which is what produces Hi-Bi, the x polarized FM is faced more loss than the y polarized FM. Because of the wise use of elliptical nesting components in the cladding region, the suggested structure's loss performance is improved when compared to the recent comparable structures [11,[21][22][23][24][26][27][28][29]. The range(from 1539 nm to 1597 nm) of 58 nm wavelengths where the CL of y-polarized FM sustains within 0.54 dB/m…”

“…Only a small number of theoretical and experimental studies have been found so far to obtainHi-Bi and PM features on HC-ARFs since researchers are now focusing on enhancingthe birefringence of HC-ARFs [11,[20][21][22][23][24][25][26][27][28][29]. For instance, despite having numerous stacked layers and four cladding tubes with a tiny core diameter of 14 µm, Mousavi et al's rst HiBi HC-ARF demonstration generated a Hi-Bi of 1.5×10 − 4 at 1550 nm with a loss of 0.043 dB/m [11,20].However, the composition consisted of four external tubing layers incorporating numerous nested resonator layers, with a relatively compact core size of 14 µm.In a numerical investigation of a six tube AR-HCF with two nested elements, a low birefringence of 1.3×10 − 5 at 1550 nm with a CL of 0.02 dB/m was obtained [22].Additionally, the six-tube bi-thickness HC-ARF developed by Yerolatsitis and colleagues [24]had a lower birefringence of 2.5×10 − 5 and a higher loss of 0.46 dB/m at 1550 nm.…”

An Ultra-Low Bending Loss Negative Curvature Hollow Core Fiber With a Polygon Jacketing Layer

“…1 shows the cross-section of the proposed modified nested 2SCF (MN-2SCF) with a polygonal jacketing layer. Unlike conventional HC-ARFs [31][32][33][34][35], a tube with a polygonal inner boundary was introduced as the jacketing layer of the fiber. The single-ring HC-ARF with a polygonal jacketing layer has been explored numerically and experimentally [33].…”