Bend radius

About: Bend radius is a research topic. Over the lifetime, 3303 publications have been published within this topic receiving 35415 citations. The topic is also known as: minimum bend radius.

Design of a compact and broadband terahertz polarization splitter based on gradient dual-core photonic crystal fiber

Abstract: We report a broadband polarization splitter based on polyethylene photonic crystal fiber with microstructured dual refractive index gradient cores. These dual cores consist of a properly optimized arrangement of air holes such that for individual fibers x-polarized modes have large effective indices difference, while this index difference is almost zero for their y-polarized modes, leading to efficient coupling between the y-polarized modes. We have shown that by proper optimization of gradience created in the arrangement of air holes, efficient polarization splitting can be achieved for a broad range of terahertz frequencies. Device length and extinction ratio have been calculated numerically for the proposed configuration. Device length of ∼1.96 to ∼60cm was found to be appropriate for frequencies in the 0.4–1.0 THz range to have high extinction ratios: −38 to −49dB and −15 to −23dB for the x and y polarizations, respectively. The bending loss for the proposed design is quite low: ∼0.05dB/m at 1 THz for the bend radius of 1 cm. These results suggest that a compact, low-loss, and broadband polarization splitter with very high extinction ratios can be achieved by wrapping the fiber around a small mandrel.

Modular bend radius control fixture

Abstract: A reconfigurable modular bend radius control fixture system allows for customization of bend module sections to achieve a variety of configurations with only a minimal number of different parts. The system includes at least one main section having a curved surface with a predetermined radius that provides a first bend radius control surface and side walls, at least one straight side plate section removably mountable to the side walls of the main section, the side plate section having a side wall that extends beyond the curved surface when mounted, and at least one bend radius control side plate removably mountable to the side walls of the main section. The bend radius control side plate section forms a second bend radius control surface. These sections can be mounted in various configurations to form a bend radius control fixture that can be mounted to a mount member of a cable management system, such as a ladder rack. The fixture is particularly suited for assisting management of sensitive cabling, such as fiber optic cabling or category 5 and 6 cabling.

Stackable bend radius guide

Abstract: A device for providing microbending and bend radius protection for cables in a cable distribution or management system. The device includes an arcuate member of radius greater than or equal to the minimum bend radius of a prescribed cable, a plurality of flanges disposed on the arcuate member perpendicular to the longitudinal axis of the arcuate member, a quarter turn fastener, an opening for receiving the quarter turn fastener, a plurality of protuberances, and a plurality of recesses for receiving the protuberances.

Polarization mode dispersion in a coil of single-mode fiber

Abstract: Polarization mode dispersion resulting from lateral stress by bending is measured as a function of bending curvature. The magnitude of the modal dispersion is found to be 286 psec/km for a bending radius of 2.8 mm. The experimental result is in good agreement with that predicted theoretically for bulk material.

Secondary cells and separation in developing laminar curved-pipe flows

Abstract: Laminar flows through 180° curved bends of circular cross section are investigated numerically. For small curvature ratio, α, defined as pipe radius over mean bend radius, the governing equations could be parabolized. The equations are solved for an α range of from 0.04 to 0.143, a Dean number (De) range of from 277.5 to 1360, and for a uniform flow, a potential vortex, and a parabolic flow inlet condition. In all these studies a zero cross-stream flow at the inlet is assumed. A detailed study of the effects of α, De, and inlet condition on the secondary flow pattern is carried out. Within the range of parameters investigated, up to three secondary cells are found in the cross-stream half-plane of a curved pipe. They are the Dean-type secondary cell, a secondary separation cell near the inner bend (closest to the center of curvature of the bend), and a third cell near the pipe center. The number of secondary cells in the cross-stream half-plane is greatly influenced by the inlet flow, and to a much lesser extent by α and De. For example, only the Dean cell is found in a curved-pipe flow where α and De are small and the inlet flow is either uniform or a potential vortex. When the inlet condition of the same case is changed to a parabolic flow, a three-cell structure results. Furthermore, as De increases to 1180, incipient axial flow separation begins at around 23° downstream of the curved-pipe entrance. The formation and extent of the separation and third cells are investigated together with their dependence on the parameters studied. This investigation further shows that, within the range of parameters examined, there is no secondary cell occurring near the outer bend, contrary to some earlier findings on fully developed curved-pipe flows.