204 results about "Propagation constant" patented technology

Optical plasmon-wave attenuator and modulator structures for controlling the amount of coupling between an guided optical signal and a surface plasmon wave. Optical power coupled to the plasmon wave mode is dissipated in varying amounts producing an intensity modulation effect on the optical signal. For electrical modulation, an additional dielectric (or polymer) layer with variable refractive index in optical contact with a metal layer supporting at least one plasmon wave mode is used to perturb or vary the propagation constant of plasmon wave. Propagation constant variation results in the power coupling variation between the surface plasmon wave and the optical wave. The refractive index variation of the dielectric (or polymer) layer can be accomplished via an electro-optic traveling-wave, a lump-element, or any other integrated optics modulator configuration situated to affect the layer, thereby permitting data rates into tens of GHz. Because of the extremely small interaction lengths needed, the optical plasmon-wave modulator is a very compact device which can be implemented on the top of a fiber or as an integrated optical planar structure.

High-speed optoetectronic devices having a waveguide densely integrated with and efficiently coupled to a photodetector are fabricated utilizing methods generally compatible with CMOS processing techniques. In various implementations, the waveguide consists essentially of single-crystal silicon and the photodetector contains, or consists essentially of, epitaxially grown germanium or a silicon-germanium alloy having a germanium concentration exceeding about 90%.

High-speed optoelectronic devices having a waveguide densely integrated with and efficiently coupled to a photodetector are fabricated utilizing methods generally compatible with CMOS processing techniques. In various implementations, the waveguide consists essentially of single-crystal silicon and the photodetector contains, or consists essentially of, epitaxially grown germanium or a silicon-germanium alloy having a germanium concentration exceeding about 90%.

The present invention's multimode optical fiber is characterized in that the propagating modes include a mode the lowest and second or higher order modes; and the difference between the propagation constants of the lowest order mode and the second order mode is 2-fold or more than the difference between the propagation constants of adjacent modes that are second order or higher order modes. Due to this design, single mode propagation becomes possible once the modes have propagated over a specific distance. As a result, it is possible to relax the conventional single mode conditions, enabling the fiber parameters to be set relatively freely.

A transmission line microwave apparatus includes at least one nonreciprocal transmission line part, which includes a series branch circuit equivalently including a capacitive element and a shunt branch circuit equivalently including an inductive element. The nonreciprocal transmission line part has gyrotropic characteristic by being magnetized in a magnetization direction different from the propagation direction of a microwave, and has an asymmetric structure to a plane formed by the propagation direction and the magnetization direction. The nonreciprocal transmission line part has a propagation constant and an operating frequency set in a dispersion curve that represents a relation between the propagation constant and the operating frequency so that the propagation constant in the forward direction and the propagation constant in the backward direction have nonreciprocal phase characteristics different from each other. A microwave transmission line is constituted by cascade-connecting at least one non-reciprocal transmission line part between first and second ports.

For the cost effective implementation of negative-index refraction, an anisotropic hyperbolic planar metamaterial comprising a first set of substantially parallel, unloaded and coplanar transmission lines, said first set being spaced with a periodicity dy a second set of substantially parallel, unloaded and coplanar transmission lines, said second set being spaced with a periodicity dx, further being coplanar and substantially orthogonal with said first set of transmission lines, wherein the periodicities of said first set and second set of transmission lines being governed by the relationship βx(fr)dx+βy(fr)dy=2π, where: βx and βy are the intrinsic propagation constants of electromagnetic waves of frequency fr propagating along the first and second set of transmission lines, respectively.

A dual-band resonator with compact size, such as a resonant type dual-band antenna, which uses an anisotropic metamaterial is described. The artificial anisotropic medium is implemented by employing a composite right / left-handed transmission line. The dispersion relation and the antenna physical size only depend on the composition of the unit cell and the number of cells used. By engineering the characteristics of the unit cells to be different in two orthogonal directions, the corresponding propagation constants can be controlled, thus enabling dual-band antenna resonances. In addition, the antenna dimensions can be markedly minimized by maximally reducing the unit cell size. A dual-band antenna is also described which is designed for operation at frequencies for PCS / Bluetooth applications, and which has a physical size of 1 / 18λ0× 1 / 18λ0× 1 / 19λ0, where λ0 is the free space wavelength at 2.37 GHz.

The invention provides an optical fiber sensor capable of simultaneously measuring the hydrogen concentration and the temperature. The optical fiber sensor comprises a wide-spectrum light source 1, a sensing unit 2 and a spectrometer 3. The sensing unit 2 is composed of a single-mode optical fiber 21, a coreless optical fiber 22 and a single-mode fiber grating 23. The outside of the coreless optical fiber 22 is plated with a palladium-based hydrogen sensitive film. The light emitted from the wide-spectrum light source 1 passes through the single-mode optical fiber 21 to enter the coreless optical fiber 22, and is excited at a plurality of higher order modes within a fusion area 24. In the above modes, the lights are propagated inside the coreless optical fiber at different propagation constants and interfere with each other. An interference light signal enters the single-mode fiber grating 23, and will be reflected when meeting the Bragg reflection condition of the single-mode fiber grating 23. When the external hydrogen concentration changes, the interference spectrum will move. When the ambient temperature changes, both the interference spectrum and the Bragg reflection wavelength will move. Therefore, the hydrogen concentration and the temperature can be deduced through observing the movement amount of the interference spectrum and the movement amount of the Bragg wavelength. As a result, the high-precision measurement of the hydrogen concentration can be realized.

The present invention provides a method and apparatus for a monolithic device utilizing cascaded, switchable slow-wave CPW sections that are integrated along the length of a planar transmission line. The purpose of the switchable slow-wave CPW sections elements is to enable control of the propagation constant along the transmission line while maintaining a quasi-constant characteristic impedance. The device can be used to produce true time delay phase shifting components in which large amounts of time delay can be achieved without significant variation in the effective characteristic impedance of the transmission line, and thus also the input / output return loss of the component. Additionally, for a particular value of return loss, greater time delay per unit length can be achieved in comparison to tunable capacitance-only delay components.

A novel in-fiber polarizer is provided that is implemented in an optical fiber structure based on a polarization maintaining (“PM”) optical fiber, and that is configured to impart a predetermined desired polarization to a light signal transmission of a predetermined at least one wavelength transmitted therethrough. The inventive polarizer comprises a PM optical fiber structure, with an entry end for receiving incident light and an exit end for outputting polarized light, having an optical fiber core, having at least one core mode and a core propagation constant, surrounded by a cladding, having at least one cladding mode and a cladding propagation constant, that further comprises a reduced core diameter region of a predetermined length between its entry and exit ends, wherein various predefined parameters of the modified PM optical fiber structure, including but not being limited to, the core and cladding propagation constants, the value of the reduced core diameter, and the length of the reduced core diameter region are selected and configured to produce a constructive interference for one light polarization of the input light signal, corresponding to the desired polarization, and to produce a destructive interference for a polarization orthogonal to the desired polarization, to thereby only output, at the polarizer exit end, the desired polarization component of the light signal transmission at the at least one wavelength. Additional embodiments of the inventive polarizer include multiple sequential polarizer structures with specially configured interconnects.

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.

Disclosed is an electromagnetic wave transmission device with regulative and controllable magnetic field based on sub-monolayer wavelength metal grating; the device comprises a sub-monolayer wavelength metal grating and magnetoactive medium filled in the slit of the sub-monolayer metal grating; the metal part of the device and the magnetoactive medium have the same thickness, the thickness at least meets and supports the lowest-level Fabry-Perot cavity resonance demand of the designed work wavelength in the grating slit; the period and slit of the grating are shorter than the wavelength of the electromagnetic wave. By changing the size of the additional magnetic field, the propagation constant of the waveguide mode in the metal grating slit can be regulated to change the electromagnetic transmission characteristic of the device and realize the purpose of initial regulation of polarization-independent electromagnetic wave transmission spectrum and the electromagnetic wave transmission spectrum magnetic field.

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.

The invention discloses a radio frequency noise de-embedding method, which comprises the following steps of: forming a device under test, an open de-embedding test structure and a thru de-embedding test structure on a silicon chip; performing tests to obtain scattering parameters of the device under test, the open de-embedding test structure and the thru de-embedding test structure and a noise parameter of the device under test; and performing de-embedding calculation by utilizing each scattering parameter and the noise parameter of the device under test to obtain a noise parameter of a radio frequency device, wherein the normalized characteristic impedance and propagation constant of a pure metal wire are calculated by utilizing the scattering parameters of inter-signal metal wires of the thru de-embedding test structure, and then an ABCD parameter of an input end metal wire or an output end metal wire of the device under test is calculated. By the method, the number of the thru de-embedding test structures on the silicon chip can be greatly decreased, the area of the silicon chip can be saved, test time can be shortened, and cost can be greatly decreased.

An apparatus and associated method for controlling the propagation constant of a region of focusing propagation constant in an optical waveguide. The method comprising positioning an electrode of a prescribed electrode shape proximate the waveguide. A region of focusing propagation constant is projected into the waveguides that corresponds, in shape, to the prescribed electrode shape by applying a voltage to the shaped electrode. The propagation constant of the region of focusing propagation constant is controlled by varying the voltage. Light of certain wavelengths passing through the region of focusing propagation constant has a variable focal length.

A multiple-fiber, stretched, fused and cleaved coupler designed to act as an output window to a fiber laser array or fiber-coupled laser array, in which the stretch, length and / or position of the fibers is chosen facilitate the in-phase oscillation of the lasers in the array. The in-phase oscillation of the lasers is facilitated by making one or more of the fibers interferometrically dark and having a different propagation constant than the other fibers. The other fibers, the interferometrically lit ones, are made to have fairly uniform intensity under the same collimated illumination.

Methods are provided for reducing interference from stray currents in buried pipelines / metal structures during MEIS testing or other current-sensing applications in the pipeline. Methods are also provided for measuring bulk complex electrical impedance between a buried pipe and the soil, thereby rendering an indication of the quality of the anti-corrosive coating. Methods are also provided for measuring the complex propagation constant of AC voltages propagating along an attenuative pipeline. This information is useful for assessing the general condition of the anti-corrosive coating involved, or to enhance MEIS inspection of the pipeline. Methods are also provided for enhancements to MEIS testing, including (a) canceling magnetometer offset effects associated with the Earth's magnetic field after the magnetometer is positioned for measurement, (b) implementing a separate sensing connection to the pipe so as to avoid interference from voltage loss in the pipe feed-line connection, (c) providing a power amplifier to excite the pipe with large-amplitude signals.

There is disclosed an optical fiber wherein an absolute value of the fourth order dispersion β4 of fourth derivative β4 of propagation constant β with respect to angular frequency ω at a mean zero dispersion wavelength λ0 in an overall length is not more than 5×10−56 s4 / m and wherein a fluctuation of a zero dispersion wavelength along a longitudinal direction is not more than ±0.6 nm.

A system and method for using loop topology identification to investigate a transmission line having a plurality of cable segments. At a measurement plane for each segment, a probing signal is transmitted into the cable. A reflected signal is detected, and an equivalent total input impedance is calculated. The system iteratively calculates the distance between the measurement planes as well as the length, characteristic impedance, and the propagation constant of each segment. A model is used to calculate the respective equivalent input impedance of each segment using the calculated characteristic impedance, propagation constant, and length of the preceding segment. The equivalent total input impedance is then calculated from the iteratively calculated segment values.

The present invention provides an organic light emitting diode substrate configured so that the light extraction efficiency of a single color organic light emitting diode element made from one type of light emitting material is high, so that there is no risk of an extraction wavelength deviating from a target light emission wavelength due to slight variations in a fine uneven structure, and so as to enable extraction of a narrow bandwidth of light, from visible light, that has any central wavelength within the near infrared band and that has a degree of broadness. Also provided are an organic light emitting diode, a manufacturing method for the organic light emitting diode substrate, a manufacturing method for the organic light emitting diode, an image display device, and an illumination device. The organic light emitting diode, which is a top emission-type, is configured so that at least the following are laminated on the substrate: a reflective layer comprising a metal material; an anode conductive layer comprising a transparent conductive material; an organic EL layer having a light emitting layer which contains an organic light emitting material; and a cathode conductive layer in which a semi-transmissive metal layer and a transparent conductive layer comprising a transparent conductive material are laminated. On the surface of the semi-transmissive metal layer that is in contact with the transparent conducive layer side, a two-dimensional lattice structure is formed in which a plurality of protrusions are arranged periodically and two-dimensionally. If in the surface the real part of propagation constant of a surface Plasmon expressed by complex numbers is k, a distance between centers (P), which is the distance between centers (P) of adjacent protrusions from among the protrusions formed on the surface, is set to be a value within the range of formula (1). When forming a triangular lattice structure as the two-dimensional lattice structure, P0 in formula (1) satisfies formula (2), and when forming a rectangular lattice structure as the two-dimensional lattice structure, P0 satisfies formula (3).[MathematicalFormula1]0.8P0≤P≤1.2P0(1)[MathematicalFormula2]P0=4π√3k(2)[MathematicalFormula3]P0=2πk(3)

In a multicore fiber in which multiple single mode cores are stored in one optical fiber, the multicore fiber has a lattice-point arrangement in which multiple lattice points are periodically arranged two-dimensionally with translational symmetry and rotational symmetry or one of translational symmetry and rotational symmetry and, in that lattice-point arrangement, multiple cores are arranged with the lattice points of the lattice-point arrangement as reference positions. By giving different perturbations to the propagation constants of the cores, the propagation constants of the cores are each varied from the original propagation constants. Because of the variation in the propagation constants, the core-to-core coupling amount, which is dependent on the varied propagation constants, fall below a predetermined setting amount. Suppressing the coupling between homogeneous cores in this way reduces the distance between the homogeneous cores, thus increasing the core density of the multicore fiber without increasing the types of heterogeneous cores.

In order to locate a cable fault in a cable, a testing apparatus applies a test signal to the cable so as to induce an electrical oscillation. The testing apparatus includes a voltage source that generates the test signal, which e.g. ignites an electrical arc at the cable fault or applies a voltage surge to the cable, to cause the electrical oscillation. The apparatus further includes a measured signal evaluation device to measure the resulting oscillations in the time domain or the frequency domain, and carry out a spectral analysis in the frequency domain, so as to automatically determine the location of the fault preferably from the total phase rotation of the signal, the phase rotation of the reflection at the first cable end, the phase rotation of the reflection at the cable fault, and the imaginary part of the propagation constant of the signal in the cable.

An apparatus and method for transmitting a plurality of light signals is disclosed. The apparatus includes a splitter configured to split an incoming light signal into a plurality of light signals. Phase control units are included which modify the phase of the light signals. Waveguides are coupled to the phase control units. Each waveguide has a different propagation constant, that is different from adjacent waveguides and the difference between the propagation constants of any two adjacent waveguides is substantially larger than an effective coupling constant between said two adjacent waveguides. Coupling members couple the light signal in one of the plurality of waveguides to free space. The splitter may include output and / or input waveguides and a dispersion element splitting and / or combining: light.

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 multi-core fiber for accommodating multiple single mode cores in one optical fiber is provided with multiple types of non-identical cores having different propagation constants. Each of the multiple types of non-identical cores includes a core part and a cladding part covering an outer periphery of the core part. The cladding part has a double cladding structure including a first cladding for surrounding an outer periphery of the core part and a second cladding on the outer side of the first cladding. In the multiple types of non-identical cores, an optical electromagnetic profile in the core part and the first cladding is confined within a range of the core part and the first cladding, restricting a leakage thereof to the second cladding, and the propagation constant of each non-identical core is made different using the refractive index of the first cladding as a parameter.

The invention provides a novel over-mode circular waveguide broadband directional coupler and a design method thereof. According to the over-mode circular waveguide broadband directional coupler and the design method thereof, a standard rectangular waveguide in the traditional over-mode circular waveguide directional coupler is replaced with a non-standard over-mode rectangular waveguide; the cutoff wave number of a basic mode TE10 of the non-standard over-mode rectangular waveguide is changed through adjusting the size of the non-standard over-mode rectangular waveguide, and the cutoff wave number of the basic mode TE10 of the non-standard over-mode rectangular waveguide is enabled to be the same as that of a working mode TEmn in an over-mode circular waveguide, so that the propagation constant of the TE10 at any frequency point is the same as that of the TEmn, then, forward waves of the coupler can meet equidirectional superposing conditions at any frequency point, and the aims of expanding the working bandwidth of the over-mode circular waveguide directional coupler and reducing in-band coupling degree fluctuation are achieved.

Techniques for implementing series-fed antenna arrays with a variable dielectric waveguide. In one implementation, coupling elements with optional controlled phase shifters are placed adjacent each radiating element of the array. To avoid frequency sensitivity of the resulting array, one or more waveguides have a variable propagation constant. The variable waveguide may use certain materials exhibiting this phenomenon, or may have configurable gaps between layers. Plated-through holes and pins can control the gaps; and / or a 2-D circular or a rectangular travelling wave array of scattering elements can be used as well.

The invention relates to a metal film lens with nano-suture, and is characterized in that: an incident wave is firstly determined, and then proper substrate material is chosen, a layer of metal film is vapor deposited on a substrate, the incidence of the incident wave is vertical to the surface of a metal film, and then the skin depth of the incident wave in the chosen metal film is computed; the direction of X axis is chosen along the metal film, and sampling is implemented along the forward direction of X axis; then the width of the metal suture of each sample point is computed by computing the phase offset and the propagation constant of each sample point; a suture distribution along the negative direction of the X axis which is symmetrical to the suture distribution along the forward direction is chosen; finally the suture width of each sample point is obtained according to the design; then a metal film lens with nano-suture is produced by using the existing processing technology. The invention can change the suture distribution of the metal film lens according to the position of any given objective image to achieve the near field imaging or the distant field imaging, simultaneously the designed lens of the invention has simple structure, and can be used for the optical system integration extremely conveniently, the lens has extensive application prospect.

A duplexer includes: a first filter of which first and second ends connect to a common terminal and a first terminal respectively; and a second filter having a passband higher than that of the first filter, a first end and second end thereof connecting to the common terminal and a second terminal respectively, wherein a phase shifter is located neither between the first filter and the common terminal nor between the second filter and the common terminal, the second filter is a ladder-type filter including piezoelectric thin film resonators connected in a ladder shape, a propagation constant in a direction perpendicular to a thickness direction of a piezoelectric thin film in the piezoelectric thin film resonator is a real number at frequencies lower than a resonance frequency of the piezoelectric thin film resonator, and a resonator at a first stage is a parallel resonator in the second filter.

The invention relates to an electro-optic directional coupler suitable for use as a variable optical attenuator at reduced voltages compared to those known in the prior art. The present invention has found that by careful selection of an asymmetric directional coupler geometry, the transfer function of the device can be shifted so that it has an operating point between maximum and minimum transmission. Signal electrodes driven in push pull configuration advantageously use this operating point to achieve significant reduction in operating voltages for switching to maximum or minimum transmission. Asymmetry is created in the directional coupler by forming the waveguides to have different propagation constants by a difference in waveguide width, depth, index of refraction or index profile. Asymmetry can alternatively be created by causing mechanical stress in the waveguides through the placement, number, or dimensions of the electrodes, or through asymmetric dielectric structures between the waveguides and the electrodes.