122 results about "Coupling length" patented technology

A labor saving system, method, and apparatus for connecting or coupling lengths of electric metallic tubing (“EMT”). The invention uses couplings/connectors that have barbs that are designed to engage corresponding indentations on EMT to ensure proper installation. In one aspect, the invention is an EMT having: an EMT inner surface forming an EMT cavity; an EMT outer surface; an EMT first end; and at least one indentation in the EMT outer surface at or near the EMT first end, the indentation adapted to receive a corresponding barb from a sleeve device. In another aspect, the invention is a sleeve device comprising; a sleeve inner surface forming a sleeve cavity adapted to receive an end of an EMT; a sleeve outer surface; a first sleeve end; at least one barb on the sleeve inner surface at or near the first sleeve end, the barb adapted to engage a corresponding indentation on the EMT.

Threaded and coupled pipe connections are provided with a number of design features that increase resistance of the connection to fatigue failure from cyclical side loading. The features acting alone or in combination include the provision of a pin thread that is formed along a single taper and that vanishes at the surface of the pipe. The coupling engages the pin such that the threaded area of the coupling engages all of the pin threads and extends beyond the vanish point of the pin threads at the optimum coupling makeup position. The threads of the coupling and pipe may engage along both the stab and load flanks to distribute the side loading. The external surface of the coupling may be tapered from the center toward each coupling end to reduce the stiffness ratio of the connection, and the ends or faces of the coupling may be reduced in radial thickness to prevent coupling splitting. The coupling length may be extended to exceed standard coupling lengths to provide the additional threaded area and/or taper areas and/or reduced stiffness ratios.

The invention discloses a photonic crystal waveguide polarizing beam splitter which introduces a line defect to form a structure of a coupled waveguide in a two-dimensional tellurium dielectric rod photonic crystal, and implements beam splitting for TE beam and TM beam by using different coupled lengths of waveguides of the TE beam and the TM beam. The characteristics of the implementation of the polarizing beam splitter by adopting a two-dimensional photonic crystal waveguide are as follows: firstly, compared with the prior various polarizing beam splitter devices, the polarizing beam splitter adopting the two-dimensional photonic crystal waveguide can implement a polarizing beam splitting with high degree of polarization and high extinction ratio; secondly, the device can be provided with a smaller size, and can be structurally compatible with the prior photonic crystal device to meet a requirement of integration ratio; thirdly, the polarizing beam splitter adopting the two-dimensional photonic crystal waveguide has a very flexible structure, and can implement the polarizing beam splitting of any wavelength in a range from 3.5 to 35mu m for wavelengths through adjusting a length of a coupling region or a lattice constant. The invention also discloses a designing idea and a particular structural design of the polarizing beam splitter, an optical performance, etc. of the polarizing beam splitter acquired from the designing idea.

A photonic crystal directional coupler composed of at least two linear defect waveguides introduced into a photonic crystal. The medium constant and the lattice constant of the photonic crystal at the photonic crystal directional coupling part, the sizes and shapes of the elements constituting the periodical structure of the photonic crystal are varied. Thereby the difference in propagation constant between the even and odd modes of the photonic crystal directional coupling part is increased, thus shortening the coupling length of the photonic crystal directional coupler.

A broadband optical switch with high process tolerance designed and fabricated using Planar Lightwave Circuits (PLC) technology. A 2x2 configuration of the switch is based on a Mach-Zehnder interferometer (MZI) configuration that includes two 3 dB adiabatic couplers and two identical arms. Each adiabatic coupler is characterized by two straight branches having different widths, separated over a coupling length by a changing spacing therebetween and blending in a symmetric intersection area, which connect to two symmetric branches. The two adiabatic couplers are connected by the two arms with their symmetric branches facing each other along an optical propagation axis. Switch control is realized by changing an optical property of one or both of the MZI arms. Implementation in silica-on-silicon PLCs provides switches with an exceptional broadband range (1.2-1.7 mum), very high extinction ratios (>34 dB), low fabrication sensitivity and polarization independent operation.

The invention relates to a broadband optical switch with a couple of asymmetric wave guide insulation couplers, the asymmetric wave guide has a curvature variable part, the broadband optical switch comprises two insulation couples with a two multiple two structure based on Mach-Zehnder interferometer and an insulation couple with an one multiple two structure, or a Y splitter with a two multiple one structure. Each insulation couple comprises two wave guide branches with different but constant width and two symmetric wave guide branches; wherein, the two wave guide branches are provided with variable radial bend, by changing the distance between the two wave guide branches, enabling to separate the two wave guide branches within the couple length, and mixed in asymmetric crossed area.. In two multiple two switches, two insulation couplers are faced to each other along the main propagation axis in the way of mirror image via the counterpart symmetric branch, and connected with the same two arms.The insulation coupler with variable curvature is used in the silicon dioxide MZI switch on the silicon substrate, which provides the switch with a special bandwidth range (1.2-1.7 Mum), high extinction ratio (more than 35dB), low manufacture sensitivity and operations having nothing to do with polarization. The broadband optical switch has the advantages of more compact size compared with known broadband switches, less extra loss, and faster switching time and lower power consumption.

Optical switches based on the balanced bridge interferometer design require precisely made (or half a coupling length) directional couplers to achieve minimum crosstalk for the two switch outputs. Precision 3 dB-directional couplers require the waveguide dimensions and fabrication parameters of the evanescent region to be tightly controlled making a low crosstalk switch difficult to manufacture and expensive. A new type of balanced bridge interferometer type switch is disclosed where the input and output directional couplers are asymmetrically biased to induce a certain difference in the propagation constants between the two waveguide in the directional couplers. By using the asymmetrically biased directional couplers with a certain tuning a bias voltage for the directional couplers. Low crosstalk switches can be achieved for a very wide range of directional coupler strengths, relaxing the precise half-coupling length directional couplers required in conventional design. This relaxation of the precise directional coupler waveguide regions allows a relaxation in the manufacturing tolerance of the devices and therefore make the switch much easier to make. Because low crosstalk switches can be a device with an extended operating range and broader directional coupler parameters, switches can be used for a much broader wavelength bandwidth. In one of the embodiments, this new design allows a device to switch both TE and TM mode optical signals simultaneously at low crosstalk levels to result in a polarization-independent optical switch.

A method for characterizing an optical link by its beat length, coupling length and polarization mode dispersion is disclosed. A pulsed signal is sent along said optical fiber link and the backscattered signal (being a POTDR signal) is measured after passing through a polarizer. The length of said optical fiber, the average power difference between two successive minima of said backscattered signal and the number of maxima per unit length are derived. In an iterative way a beat length interval and an interval for the polarization mode coupling parameter are determined until the length of said intervals is below a predetermined value, yielding a value for the beat length and the coupling length, and the polarization mode dispersion is calculated.

A compact polarization beam splitter is formed by cascading two stages of directional couplers each containing two waveguides laid in parallel with a coupling gap. Each waveguide is made by silicon nitride material having a minimum length configured to be comparable with a coupling length for a TE polarization mode being set as twice of a coupling length for a TM polarization mode. A first-stage direction coupler is optimized by making the coupling gap smaller/greater than a nominal value to maximize TE/TM extinction ratio at least for a shorter/longer wavelength window of a designated wavelength band and each of two second-stage directional couplers is optimized by making the coupling gap greater/smaller than the nominal value to maximize TE/TM extinction ratio at least for a complementary longer/shorter wavelength window of the same designated wavelength band.

The present invention belongs to the field of fiber communication and optical signal processing, and is especially the design of double core photon crystal optical fiber as one photon device with polarizing split function. The double core photon crystal optical fiber includes one coating layer of low refractive index area formed by pore structure in regular lattice nodes and two high refractive index core areas formed by pore deletion in regular lattice nodes. The present invention features different pore size near the two core areas in two orthogonal polarization directions, unsymmetrical pore deletion, the deflection of the pore center near the core areas to the lattice nodes, or filling of polar material in the pores near the core area. Each of the core areas can produce high double refraction, so that two polarized light beams have great length difference and can be polarizing split in short distance.

The invention relates to an optical waveguide structure of a photoelectric detector for vertical coupling. The structure comprises an intrinsic layer, an absorption layer, an upper waveguide layer, a clearance layer, a lower waveguide layer, a cover layer and a substrate which are sequentially stacked from top to bottom, wherein the clearance layer is used as a low-refractive index coupling layer between the upper waveguide layer and the lower waveguide layer; and a vertical coupler (equivalent to a vertically-coupled photoelectric diode) composed of the upper waveguide layer and the lower waveguide layer is used for realizing that the light enters from the lower waveguide layer and is gradually coupled to the upper waveguide layer and transmitted in the upper waveguide layer and the lower waveguide layer while being absorbed by the absorption layer. The structure provided by the invention has the beneficial effect of overcoming the defects that the coupling length and the absorption length are changed when the air clearance in the horizontally-coupled photoelectric diode structure changes and the photoetching corrosion processing technology is difficult.

The invention relates to the technical field of optical fibers and discloses a liquid-filled double-core photonic crystal fiber. The liquid-filled double-core photonic crystal fiber comprises two fiber cores and a wrapping layer arranged on the outer periphery of the two fiber cores and is characterized in that a plurality air holes are arranged in the wrapping layer along the length direction ofthe wrapping layer at intervals, the projection of the air holes on the cross section of the wrapping layer are distributed in rows, the odd-number row of the air holes comprises a plurality of firstair holes with circular cross sections, and the even-number row of the air holes comprises a plurality of second air holes with elliptical cross sections; the first fiber core which is formed by the wrapping layer part between the two first air holes closest to the center of the wrapping layer is formed in the row of first air holes closest to the central axis of the cross section of the wrappinglayer, and the second fiber core which is formed by the wrapping layer part between the two first air holes closest to the center of the wrapping layer is formed in the other row of first air holes closest to the central axis of the cross section of the wrapping layer. The liquid-filled double-core photonic crystal fiber is short in coupling length, high in extinction ratio and quite suitable forbeing used to manufacture a polarization beam splitter and a coupler unrelated to polarization.

The invention belongs to the field of photoelectric technology and discloses a front end input waveguide structure of a directional coupling optical waveguide detector. The front end input waveguide structure of the directional coupling optical waveguide detector comprises a substrate layer, a covering layer, a lower waveguide layer, a gap layer, an upper waveguide layer and an absorption layer which are sequentially stacked from bottom to top. The front end face of the substrate layer, the front end face of the covering layer, the front end face of the lower waveguide layer, the front end face of the gap layer and the front end face of the upper waveguide layer are flush with one another, the absorption layer is located on the upper surface of the rear of the upper waveguide layer, the gap layer is a coupling layer, and the distance from the front end face of the absorption layer to the front end face of the upper waveguide layer is twice of the coupling length. The front end input waveguide structure overcomes the defects of a waveguide detector and a horizontal direction coupling waveguide detector, light current can be effectively increased, and the problem that the front end of a waveguide is overheated and burnt because of the pattern evolution problem is solved.

An organic light emitting diode comprising a light extraction substructure and a diode superstructure is provided. The light extraction substructure comprises a light expulsion matrix distributed over discrete light extraction waveguide elements and a waveguide surface of the glass substrate. The light expulsion matrix is distributed at varying thicknesses to enhance the planarity of a diode superstructure-engaging side of the light extraction substructure and to provide light expulsion sites at the waveguide element termination points of the discrete light extraction waveguide elements. In operation, light originating in the organic light emitting semiconductor material of the diode superstructure is coupled to the discrete waveguide elements of the light extraction substructure as respective coupled modes characterized by an approximate coupling length defined as the propagation distance required for an optical mode to be coupled from the superstructure waveguide to one of the discrete waveguide elements of the light extraction substructure.

The invention discloses a polarization beam splitter. The polarization beam splitter comprises a first input port 1 or a second input port 2, a coupling area 5, a first output port 3, and a second output port 4. The first input port 1 or the second input port 2 is connected with the input port of the coupling area 5, and the first output port 3 and the second output port 4 are connected with the output port of the coupling area 5. The coupling area 5 is formed by two adjacent optical waveguides, which are disposed in evanescent field ranges of waveguide modes of opposite sides. In the coupling area 5, grating structures of preset quantity are connected with the two waveguides, and are extended toward the outer sides of the two waveguides by preset lengths, and then a coupling length of a transverse electric wave TE is a half of a coupling length of a transverse magnetic wave TM. The polarization beam splitter provided by the invention is advantageous in that by adopting a function of gratings regulating and controlling a waveguide mode equivalent refractive index, an equivalent refractive index between the odd symmetric mode and the even symmetric mode of the TE is twice that of the TM, and the coupling length of the TE is a half of that of the TM, and therefore polarization beam splitting is realized.

The invention relates to a polarizing coupler based on double-core photonic crystal fibers mixed with a metal wire. The polarizing coupler based on the double-core photonic crystal fibers mixed with the metal wire is characterized by comprising background materials, cladding, a first fiber core, a second fiber core and the metal wire. The background materials are silica glass materials. Air holes arranged in a regular hexagon structural cycle mode are formed in the background materials to form the cladding. The first fiber core and the second fiber core are symmetrically located on two air hole defects in the center of the cladding. Metal materials are filled in one or two air holes to form the metal wire, wherein the one or two air holes are arbitrarily selected in the cladding. According to the polarizing coupler based on the double-core photonic crystal fibers mixed with the metal wire, the transmissivity of two cross-polarized components and coupling lengths of the two cross-polarized components are different, control over the transmissivity of output light and a polarization state can be achieved, and the functions of polarization separation and polarization filtering are achieved. The polarizing coupler based on the double-core photonic crystal fibers mixed with the metal wire has the advantages of being wide in operating bandwidth, stable in performance and capable of achieving the functions of polarization separation and polarization filtering.

The invention discloses a photonic crystal fiber polarization beam splitter provided with a two-dimensional periodical structure of photonic crystal fiber. The periodical structure is constituted by a background medium and periodically distributed dielectric rods arranged in the medium; the cross section is a parallelepiped; a periodically arranged defect area without single dielectric rod in the background medium is a waveguide core. The advantages of the photonic crystal fiber polarization beam splitter are: easy to achieve stable isophotal power or a certain percentage of splitting ratio, small structural size, not vulnerable to the impact of environmental conditions, small light loss, good polarization of polarized coupling and easy to design. The invention can select different coupling length through structural adjustment to achieve splitting ratio regulation and splitting function.

The invention discloses a tunable polarization beam splitter of a magnetic fluid filled double-core photonic crystal fiber, and belongs to the fields of special fibers, fiber communication and signal processing. The polarization beam splitter is based on a double-core photonic crystal fiber structure. The double-core photonic crystal fiber comprises a pure quartz substrate (1), two identical cores (2) and air holes arranged periodically, and the air holes (3) on the upper and lower sides of the cores, the air holes (3) on the left and right sides of the cores and the air holes (5) away from the cores are different in radius. The air holes (6), close to the cores, of the double-core photonic crystal fiber are filled with magnetic fluid. The polarization beam splitter adopts single-channel output. The refractive index of the magnetic fluid is changed along with the intensity of an external magnetic field, and when the outside does not have a magnetic field, the polarized light in a single direction is output by the output end of the double-core photonic crystal fiber, while the other polarized light is not output. When a certain magnetic field is applied from the outside, the coupling length of the two beams of polarized light is changed with the change of the refractive index of the magnetic fluid, so that the energy of the polarized light at the output end is reduced, but the energy of the other polarized light is increased. In certain magnetic field intensity, the polarization mode at the output end of the double-core photonic crystal fiber is converted, so that the polarization mode is tunable.

A tire for vehicles carrying heavy loads, comprising in at least one bead an additional reinforcement composed of a plurality of discontinuous reinforcing elements, these discontinuous reinforcing elements being orientated essentially circumferentially to form a plurality of circles C, C1, C2 concentric on the rotation axis of the tire mounted on its rim, each circle being defined by a mean radius (R, R1, R2) measured relative to the said rotation axis, and wherein

• [0001]
  • each discontinuous reinforcing element of length L0 located on a circle C of radius R is mechanically coupled over coupling lengths L11 and L12 with two discontinuous reinforcing elements located on a circle C1 of radius R1, this circle being immediately adjacent to the circle C, the coupling length L11 being between 55 and 75% of L0 and the coupling length L12 being between 10 and 30% of L0;
  [0002]
  • each discontinuous reinforcing element on the same circle C of radius R is mechanically coupled over coupling lengths L21 and L22 with two discontinuous reinforcing elements located on a circle C2 of radius R2 immediately adjacent to the circle C1, the coupling length L21 being between 20 and 40% of L0 and the coupling length L22 being between 45 and 65% of L0.