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.

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.

3.5-μm radius race-track microlasers operating at room temperature with 1.3-μm quantum dot active region

Abstract: We present detailed studies of optically pumped InAs/InGaAs quantum dot based racetrack microlasers with 3.5-μm bend radius operating at room temperature. Q factor over 8000 and room temperature threshold power in the mW-range were achieved in the racetrack microlasers with straight section length ranging from 0 to 4 μm. A systematic investigation of the influence of the racetrack straight section length on spatial distribution of optical modes is presented. The microcavity eigenmodes and electromagnetic field distribution calculated by means of three-dimensional numerical simulation demonstrate a good agreement with the experimental results obtained by micro-photoluminescence and scanning near-field optical microscopy. The racetracks demonstrate zigzagging behavior of the modes inside the cavity and the energy switching between the radial maxima in second-order modes. Higher-order modes are found to be suppressed in micro-photoluminescence spectra.

Low loss GaInNAs/GaAs gain waveguides with U-bend geometry for single-facet coupling in hybrid photonic integration

Abstract: We report a low loss U-bend waveguide for realization of GaAs-based gain elements employed in hybrid photonic integration. This architecture allows us to position the input and output ports of the gain waveguide on the same facet and thus alleviates the geometrical constrains in hybrid integration, i.e., the need for precise alignment with silicon photonic waveguides on both ends of the III–V chip. As an exemplary demonstration, we report the loss and gain characteristics of GaInNAs/GaAs U-bend waveguides operating at 1.3 μm. In particular, we demonstrate a bending loss as low as 1.1 dB for an 83 μm bending radius. Efficient laser diode operation is also demonstrated.

Cable bending radius detection tool

Abstract: The utility model discloses a cable bending radius detection tool, which comprises a cable bending radius detection device, wherein the cable bending radius detection device comprises a fixed rod, an arc-shaped flitch, connecting rods, a retaining clip and an adjusting knob; the adjusting knob can be movably arranged on the fixed rod; the middle of the arc-shaped flitch is fixedly arranged on the top end of the fixed rod; one ends of the two connecting rods are both movably connected with the adjusting knob by the retaining clip; the other ends of the two connecting rods are respectively movably connected to one side part of the arc-shaped flitch; the bending radius of the arc-shaped flitch is regulated on the position of the fixed rod by the adjusting knob; and the fixed rod is marked with a scale used for displaying the bending radius of the arc-shaped flitch. According to the cable bending radius detection tool disclosed by the utility model, the accurate measurement of the cable bending radius and the measurement and the control of a bending critical value can be realized, and the cable laying is effectively guaranteed to achieve the uniform bending radius or guaranteed to be not less than a certain fixed bending radius value, thereby being convenient for subsequent cable construction, being convenient to use, and saving time and labor.

Development of Failure Pressure Evaluation Model for Internally Well Thinned Piping Components

Abstract: The purpose of this study is to develop failure pressure evaluation models, which are applicable to straight pipes and elbows containing an internally wall thinning defect induced by flow-accelerated-corrosion (FAC). In this study, thus, three dimensional finite element (FE) analyses are performed to investigate the dependences of failure pressure of internally wall thinned pipe on the defect shape, the pipe geometry, and the defect location and bend radius of elbow. Also, the existing failure pressure assessment models for externally wall thinned pipes are examined. Based on these, the new models for assessing failure pressure of piping components with an internally wall thinning defect are proposed. Comparison of failure pressure, predicted by proposed models, with FE analysis result shows good agreement regardless of pipe type, defect shape, and defect location and bend radius.