Showing papers on "Bend radius published in 2006"

Shape-Retaining Fiber Optic Cables Having Limited Bend Radius

Abstract: In accordance with this invention, fiber optic cables are provided whose shape may be formed and retained while maintaining a limited bend radius These features are produced by incorporating a compact compliant internal cable member into the cable structure The compliant internal member consists not only of the fiber optic cable, but also of ductile and non-ductile elements The ductile element is advantageously a tube or a wire which readily deforms to retain a given shape, and may be reshaped if desired The non-ductile element, which resists sharp bending of the cable during shaping, comprises a substantially non-ductile elongated element disposed within the cable and configured to oppose excessively sharp bending along its length Proper selection of the cross-sections and materials used in these elongated members produces a proper balance between shape retention and bending radius

Characteristic analysis of nanosilicon rectangular waveguides for planar light-wave circuits of high integration

Abstract: When a full-vectorial finite-difference method is used, rectangular Si waveguides can be characterized for planar light-wave circuits of high integration. The single-mode condition for a rectangular Si waveguide is obtained first. The birefringence, which can be adjusted by modifying the thickness of the cladding layer, is also studied. For a nano-Si rectangular waveguide the pure bending loss is very small even for an ultrasmall bending radius (e.g., a few micrometers), and the transition loss becomes dominant. The width and height are optimized to minimize the bending radius for the requirement that the bending loss is smaller than 0.1 dB. Finally the coupling between two parallel straight waveguides is analyzed, and it is shown that there is an optimal width for the maximal coupling length.

Development of multi-step processing in silicon-on-insulator for optical waveguide applications

Abstract: Multi-step processing for a silicon-on-insulator (SOI) platform was developed. It allows the incorporation of additional grooves and steps into the basic optical waveguide structures, so that light can be adiabatically coupled between waveguides with different cross-sections. The processes were based on simple fabrication methods easily scalable for mass production. Two options for the fabrication sequence were tested, both having one silicon etch step with an oxide mask and another etch step with a resist mask. The applicability of the developed processes was tested with different waveguide structures. An additional groove etched beside a bent 10 µm thick rib waveguide suppressed the bend losses to below 1 dB/90° with a 5 mm bending radius. A waveguide mirror exhibited optical losses below 1 dB/90°. The excess losses of a vertical taper between 10 and 4 µm thick rib waveguides were 0.7 dB. A converter between a rib and a strip waveguide showed negligible losses, below 0.07 dB.

Deeply Etched $\hbox{SiO}_{2}$ Ridge Waveguide for Sharp Bends

Abstract: A deeply etched SiO2 ridge waveguide including the buffer, core, and cladding is presented for realizing sharp bends. The present SiO2 ridge waveguide has a strong confinement at the lateral direction, while it has a weak confinement at the vertical direction. Due to the strong confinement, a sharp bend (with a very small bending radius of about 10 mum) is obtained for an acceptable bending loss. A detailed analysis of the loss in a bent waveguide is given by using a finite-difference method. In order to reduce the transition loss, a narrow bending section with an optimal lateral offset is used. A low leakage loss is obtained by using wide straight waveguides, and linear tapers are used to connect the wide straight section and narrow bent sections

Strain relief boot for cable connector

Abstract: A strain relief boot for a connectorized cable. The boot has a staged bending characteristic in that there are discrete first and second zones that have different bending and minimum bend radius characteristics. The boot is of a segmented design including multiple links separated from one another by open gaps that are spaced from one another in a longitudinal direction. Gaps are positioned along a periphery of the boot for each axial location. Ribs extend longitudinally to connect axially adjacent links, and to separate peripherally spaced gaps. The different characteristics relate to differences in the gap, link and rib structures, which have dimensions varying along the boot's length. Preferably, link and rib dimensions are relatively smaller toward a proximal end of the boot, and gap dimensions are relatively larger toward the proximal end of the boot. This provides greater flexibility and smaller minimum bend radii toward the boot's proximal end.

Submillimeter radius bendable organic field-effect transistors

Abstract: We have successfully fabricated ultra-flexible pentacene field-effect transistors (FETs) with a mobility of 0.5 cm 2 /V s and an on/off ratio of 10 5 , which are functional even at a bending radius ( R ) smaller than 1 mm. The FETs are manufactured on a 13-μm-thick plastic substrate and encapsulated by a 13-μm-thick parylene passivation layer, thus placing the FET in the neutral plane. We measured the electrical properties of FETs under varying compressive and tensile strains, by changing the bending radius of the substrate. If the bending radius is larger than 2 mm, the mobility changes less than 3%. Further decrease in bending radius causes larger change in mobility. At R = 0.5 mm, the mobility increases by 20% in compression or decreases by 30% in tension.

Cable support assembly for minimizing bend radius of cables

Abstract: A cable support assembly for routing electrical, communication, or data cables throughout a building. The cable support assembly includes cable trays and brackets for securing the cable trays to an overhead structure. Tray couplers are provided for coupling trays together. The brackets include a base member and a hinge arm pivotally attached to the base member. The brackets are first secured to the overhead structure to establish a desired path for the cables. The hinge arms on the installed brackets are pivoted downwards and a cable tray section inserted therein. The hinge arms and cable tray sections may be rotated upwards and latched to the base members to lock the cable trays in place. Adjacent cable trays may be joined with couplers to create a cable support assembly in which the cable tray provides support for any electrical, communication, or data cables installed therein.

Portable Flexible and Extendable Drain Pipe

Abstract: A flexible collapsible corrugated drain pipe has a corrugation structure that permits a tight bending radius and relatively facile collapsing and expansion of corrugations, thereby permitting convenient manipulation and installation of drain pipe and packaging, display, storage and transportation of the collapsed pipe sections.

Design of All-Solid Bandgap Fiber With Improved Confinement and Bend Losses

Abstract: We propose a new design of low-contrast all-solid bandgap fiber with low confinement and bend losses within low-order bandgaps. By introducing an index depressed layer around the high index rod in fiber cladding, we theoretically predict that the confinement loss of the proposed all-solid bandgap fiber would be significantly improved. Due to the enlarged index mismatch of the guided core mode and the edge of the bandgaps, the critical bend radius of the proposed fiber is remarkably reduced

Method and apparatus for multi-directional fiber optic connection

Abstract: A method and apparatus are disclosed that permit multi-directional fiber optic connections to a device. The multi-directional aspect of the fiber optic connections permit the connections to be aligned closely with the direction of travel of the fiber optic cables that interface with the device. Closely aligning the fiber optic connections on the device with the fiber optic cables' direction of travel maximizes the bend radius of the fiber optic cable near the point of connection or eliminates the bend altogether and reduces the likelihood of a broken fiber or signal attenuation.

Experimental evaluation of curved polymer waveguides with air trenches and offsets

Abstract: Excess waveguide bend loss can be minimized through the use of offsets and air trenches. Offsets, used for reducing the junction loss between straight and curved waveguides, and air trenches, which prevent bend radiation loss, were simulated by a three-dimensional, semivectorial beam propagation method. Low loss polymer waveguide bend structures, employing both offsets and trenches, were fabricated. A reduction of the 180° bend insertion loss from 17.7to3.0dB with a bending radius (BR) of 1.5mm is experimentally confirmed at λ=1.55μm. BR ranging from 5to0.5mm are evaluated with decent match when compared with simulation results. The polarization dependent loss is BR dependent with a maximum value of 0.4dB when the BR is reduced to 0.5mm. The experimental results confirm that the joint use of air trenches and junction offsets is effective in reducing the bend radii of low index contrast polymer waveguides in planar lightwave circuits.

Polarization-Dependent Curvature Loss in Silicon Rib Waveguides

Abstract: We show that the quasi-TM mode in silicon rib waveguides can experience significantly less curvature loss at the same bend radius than does the quasi-TE mode. Photonic devices making use only of the TM mode and a polarization-diversity scheme can, thus, profit from smaller possible bend radii and the resulting circuit-size reduction. The main loss mechanism for the quasi-TM rib mode can be coupling to the orthogonally polarized TE slab mode, which radiates power away from the waveguide. This is possible due to the slight hybridicity of the quasi-TM rib mode. Neglecting this hybridicity would lead to a significant underestimation of the curvature losses. Thus, accurate simulation of waveguides with low quasi-TM-mode curvature loss requires full-vectorial simulation models

Support fixture and method for supporting subscriber specific fiber optic drop wire

Abstract: Fiber optic drop wires extending from a cable closure supported along a fiber optic cable are supported by small horseshoe-shaped bend radius protectors which not only prevent overbending of the drop wires, but also enable one to store excess drop wire length on the bend radius protectors. The drop wire is secured in the channel of the bend radius protector by a retainer which has a hinge connection to the channel at one end and a latching detent portion at the other end, so that the retainer can be released when it is necessary to rerout or replace the drop wires.

Microchannel, flat tube heat exchanger with bent tube configuration

Abstract: A heat exchanger assembly includes a first header having an inlet and a second header having an outlet spaced parallel from each other. A plurality of tube members having an ultimate strength (Us) and a width (w), extend between the first header and the second header. The tube members define a plurality of fluid passages for the flow of a liquid through the tube members and between the first and second headers. The tube members extend through at least one bend having a bend radius (r) in the range of 50.00 mm to straight (∞) through angles between 0 and 100 degrees. A plurality of corrugated air fins are brazed between adjacent tube members. The bends of the tube members satisfy a bending formula (w/r)Us≦30 mega Pascal.

Resilient joint for deployable structures

Abstract: A resilient flexure has one end attached within a cavity in a rigid member, and the other end attached within a cavity in a structural mode. The cavities are shaped to limit the flexure's bend radius. The member and the node have mating surfaces that abut to constrain the amount of rotation of the member. The aforementioned elements are shaped to prevent the strain in the flexure from exceeding its design limit when the joint is at its maximum angular deflection and the attached member is fully collapsed.

Heater core connector

Abstract: A small bend radius connector for a heater core is shown, wherein a first end of the connector has a rectangular cross section, a second end of the connector has a circular cross section, and wherein a size, a weight, and a cost of production of the connector are minimized.

An Analytical Approach and Optimization of Curvature Gauge

Abstract: The 'curvature gauge' is sensor for the monitoring of deflection of structures under mechanical loading in applications in which strain gauges have traditionally been used. The sensitive zone of the curvature gage is precision machined into the plastic optical fibre on grinding or milling machines. The cut-out produced removes a part of the fibre core and introduces a loss of light propagating along. The extent of such loss is related to the bendradius of the fibre. In this work we present an analytical approach of this sensor. The operation of this curvature gauge is now explained and estimated in order to optimise it and improve its performances. The results are shown that relate the relative light-loss to the fibre curvature for different parameters (its depth, length, number of cuts, bend radius and pitch of cuts). Proposed model allows a quantitative optimization of curvature gauge without the necessity for making of the thousands of sensors with slightly different parameters in order to accomplish a similar objective experimentally.

Cable clip and cable riser integrating a cable clip

Abstract: A cable clip includes a housing defining an open space and outer grooves about the housing for mounting the cable clip into a mounting opening, the inner edge of the housing including trumpet flares around the edges of the ends and side to provide bend radius protection for cables passing through the clip and a gate closing off the open sided space. The gate may be attached to the housing by a living hinge.

Minimizing bend loss by removing material inside the caustic in bent single-mode fibers

Abstract: By removing the cladding on the outside of a bent single-mode optical fiber and exposing a surface at a radius smaller than that of the radiation caustic, the leaky nature of the propagating mode is almost suppressed, and bend loss is effectively eliminated. The practical realization of this effect is described, and a loop with a bend radius of 0.50 mm on standard telecommunications fiber is demonstrated with negligible loss.

Bending Losses in all Solid 2D Photonic Band-Gap Fibers: A limiting Factor?

Abstract: Bending losses are investigated experimentally and numerically in a solid-core bandgap fiber with parabolic refractive index inclusions Previous record of 20 dB/km is reduced to 6 dB/km by increasing the fiber bend radius

Surface waveguide technology for telecom and biochemical sensing

Abstract: Surface waveguides for telecom applications are typically SiO 2 -based, low-contrast surface waveguides because these applications are dominated by the need for low optical attenuation and low polarization effects across the 1300-1600 nm band. Conventional waveguides, however, comprise films as thick as 20 micron and have minimum bend radii of tens of millimeters. These factors make conventional waveguide circuits large and expensive, and this has limited their use to relatively few applications. In the integrated optical sensing field, the waveguides typically used are (very) high-contrast waveguides. Here, especially Si 3 N 4 -core waveguides are well-known to offer much smaller bending radii (tens to hundreds of microns) due to stronger mode confinement to the core. Since they also typically comprise sub-micron core-thickness and cladding-thickness of only a few microns, high-contrast waveguides promise lower cost than low-contrast waveguides. Their use in telecom applications has been limited, however, due to strong polarization effects. Recently, LioniX, BV has developed the TriPleX TM waveguide, which promises to be a well-suited platform for both telecom and sensing applications and is based on low-cost, CMOS-compatible LPCVD processing. TriPleXt TM technology provides high-contrast waveguides with very low channel attenuation and modal birefringence that is controlled through waveguide design alone. Early experiments on typical geometries show promising waveguide characteristics (attenuation << 0.5 dB/cm, IL ≤ -2 dB, PDL << 1 dB, bend radius << 1 mm). In this paper, we present the characteristics of this TriPleX TM technology, and show devices that have demonstrated utility in telecom and/or sensor applications using medium and high-contrast waveguides. Experimental results for an MZI-based sensor platform, suitable for liquid or gaseous sensing, are also provided.

Performance criteria for cold formed structural steels

Abstract: Overview A joint programme of work was carried out by Corus, IEHK, Labein and University of Cantabria to establish the effect of cold deformation and hole punching on the performance of structural steels with yield strengths up to 890 MPa. The principal objective of the project was to quantify the effects of these downstream processes on structural integrity and to provide guidelines for optimising fracture and fatigue performance. A range of structural steels, covering different product types, process routes, grades and thickness, were studied. The majority of the work was focussed on plate steels in the strength range 355-890 MPa with a smaller number of sections at lower strength level. The plates were characterised in the as-received and subsequently - processed conditions in terms of conventional small-scale tests. Large-scale performance in terms of fracture and fatigue was established by wide-plate tests, fatigue tests on punched plate and fracture tests on punched plates and sections. Finite Element Modelling was used for quantification of the levels of deformation and damage associated with the various processes and to study the effect of process variables on this deformation. Processing of materials All plates were successfully bent in a 2000 t press brake to 90° nominal bend angle. Strength grades 355, 460 and 690 were all pressed to between 2 and 6 t inner bend radius, representing nominal outer strains up to 20%. The 890 grade was pressed to a minimum of 2.7 t bend radius. No cracking or fractures occurred during pressing. 15 mm plates of strength grade up to 690 were all successfully punched using a standard punch design. Grade 355 plate was also punched in 25 mm thickness. In all cases good quality holes were produced with minimum conicity. Modelling Modelling of bending processes is relatively straightforward and well developed, while those for punching are complex, involve major non-linearities and require a damage criterion. ABAQUS was found to be highly suitable for the former and a modified version of FORGE2 for the latter. Two dimensional modelling is suitable for most cases, and this reduces the running time significantly. In plate bending, residual plastic strains for a given plate thickness and bend radius vary depending on grade. For bend radii down to 2 t the maximum outer fibre strains are slightly higher than those predicted from the simple elastic formula. For bends greater than 5 t the modelled and theoretical values are the same while below 2 t the stress-strain characteristics of the plate have a major influence, with higher strains remaining in the higher strength plates.

Numerical investigation of straight-line laser forming under the temperature gradient mechanism

Abstract: Laser forming is a new flexible and dieless forming technique. To achieve the high accuracy forming, the temperature gradient mechanism (TGM) is studied. In the analysis of TGM, the plate bends about x-axis and about y-axis as well. To understand the deformation trend, the numerical simulation of deformation of plate is conducted by choosing different laser powers, laser spot diameters, scanning speeds, lengths, widths and thicknesses. From the results of simulation, it can be seen that the laser spot diameter, the scanning speed, laser power and thickness of plate play dominant roles in the laser forming process. However, the bending angles αx and αy show different trends with the variation of parameters. In addition, in comparison with above four parameters, the effect of length and width of plate on the bending angle may be neglected, but their effects are significant for the bending radius R.

Cambered watch crystal

Abstract: The crystal has a convex upper face (10) and a concave lower face (12), each presenting a bend radius (RS1, RI1), along 12 hours-6 hours axis, and another bend radius, along 3 hours-9 hours axis The radiuses are such that the crystal has a constant thickness (e) The crystal is in rectangular, oval or barrel form, and is made of a hard crystalline transparent mineral material such as sapphire, spinel or ruby An independent claim is also included for equipment for multipart machining of the convex upper face of a watch crystal

Thick bendable decorative board and its manufacturing method

Abstract: The present invention relates to a flexible decorative plate whose thickness is 2-12mm. Said late can be bent to make an angle of 60-135deg.C with plane, and its bend radius can be 15-20mm. Said flexible decorative plate is made up by using decorative paper, melamine, kraft paper, phenol-formaldehyde resin and hot-melt resin. Said invention also provides its making method and concrete steps.

Forming characteristics of thin-walled tube bending process with small bending radius

Abstract: Currently requirements of thin-walled tube with small bending radius cause the defects such as wrinkling, overthinning and cross-section distortion more prone to occur in bending process. Based on the analysis of the forming characteristics by analytical and experimental methods, a complete 3D elastic-plastic FEM model of the process was developed using ABAQUS/Explicit code, including bending process, balls retracting and unloading process, and thus the plastic deformation characteristics with small bending radius were investigated. The main results show that: 1) The utmost deformation feature of the NC bending process is its continuous progressive deformation. 2) The occurring conditions of the defects such as wrinkling and tension instability in the process are obtained. The wrinkling is traditional on the double compressive stresses state and the tension instability is on the double tension stresses state. 3) The enhanced non-uniform deformation in thin-walled tube with small bending radius is demonstrated by comparing the stress/ strains distributions under the 1.5D and 1D bending conditions. 4) For ID small bending process, a new method-"stepped mandrel retraction" is proposed to improve the bending quality in experiment according to the FE simulation. The simulation results are verified by experiment.