100 results about "Higher order mode" patented technology

The invention discloses a few-mode hollow-core anti-resonance optical fiber based on a spiral cladding and a preparation method thereof. The optical fiber structure is sequentially divided into a hollow-core fiber core area, a cladding area and an outer sleeve area from inside to outside; the cladding area is formed by arranging a plurality of spiral anti-resonance structure units along the inner boundary of the outer sleeve area in the angular direction, each spiral anti-resonance structure unit is composed of spiral glass walls with the wall thickness of t, and the distance between the spiral glass walls changes along with the spiral generation direction or is kept at a specific constant. The high-order mode above a specific order is suppressed, and the suppression ratio of the high-order mode to the fundamental mode in the hollow-core optical fiber is regulated and controlled by changing the spiral type and structure parameters, so that the purpose of supporting low-loss transmission of a specific number of different-order modes is achieved. The multi-order mode low-loss transmission antenna has the characteristic of supporting multi-order mode low-loss transmission, can change a spiral line type structure and parameters according to different application scenes, is high in expansibility and feasible in preparation, and has a great application prospect in the application fields of communication, sensing, energy transmission and the like.

Intensity control units 40A and 40B acquire the intensity of backscattered light when inputting signal light of two or more modes for each core in a multicore optical fiber 10, which has two or more cores and in which two or more modes propagate to each of the cores, so that the transmission direction of light differs between adjacent cores, and output a control signal for reducing the input optical power of a high-order mode other than a basic mode of the signal light by a predetermined amount so as to reduce the influence of the high-order mode on the basic mode.

To achieve high-power single transverse mode laser, we here propose a supersymmetry (SUSY)-based triple-ridge waveguide semiconductor laser structure, which is composed of an electrically pumped main broad-ridge waveguide located in the middle and a pair of lossy auxiliary partner waveguides. The auxiliary partner waveguides are designed to provide dissipative modes that can phase match and couple with the higher-order modes in the main waveguide. By appropriately manipulating the gain-loss discrimination of the modes in the laser cavity, one can effectively suppress all the undesired higher-order transverse modes while keeping the fundamental one almost unaffected, thereby ensuring stable single-mode operation with a larger emitting aperture and accordingly a higher output power than a conventional single-transverse-mode ridge waveguide diode laser.

An MCF of one embodiment combines the adoption of a plurality of cores with different refractive indices with suppression of manufacturing costs. The MCF has a glass optical fiber having a plurality of cores and a cladding, and a resin coating. The plurality of cores includes a first core with a high refractive index and a second core with a low refractive index. On a cross-section of the MCF, an arrangement of centers of a plurality of portions has no rotational symmetry about the cross-section center, the portions having a refractive index higher than that of the cladding. Furthermore, a mode leakage adjustment structure is provided to reduce a difference between a cutoff wavelength of a residual higher-order mode in the second core and a cutoff wavelength of a residual higher-order mode in the first core.

This invention discloses a system and method for achieving single-mode transmission of sapphire optical fiber using a mechanically wound helical structure, belonging to the technical field of optical fiber transmission and high-temperature optical devices. The method involves winding sapphire optical fiber along a specific pitch to form a helical structure on a core, introducing controllable bending loss to suppress higher-order modes. Subsequently, high-temperature annealing and structural fixation ensure uniform stress distribution within the fiber and maintain a stable structure. Finally, optical testing verifies the single-mode transmission effect. This method offers advantages such as simple structure, no need for complex processing equipment, low cost, and high stability, and can be widely applied in high-temperature optical fiber sensing and high-power laser transmission.

The application provides a background noise high-order surface wave dispersion extraction method, and belongs to the technical field of seismology. The method first calculates the cross-correlation function of continuous noise data and performs preprocessing to obtain an original dispersion energy spectrum; then a reference phase shift curve between the energy of the base order and the first high-order mode is extracted; the cross-correlation function is phase-shifted based on the curve, so that the base order and the high-order surface wave are separated in time, the high-order part at the negative time is retained and inverse phase shift is performed, and a cross-correlation function containing only the high-order surface wave is obtained; then the high-order surface wave dispersion energy spectrum is obtained through frequency-Bessel transformation, and is spliced with the base order part in the original spectrum to form an enhanced dispersion energy spectrum; finally, the base order and the high-order dispersion curves are extracted after quality control. The application can effectively suppress the interference of the base order sidelobe on the high-order mode, and significantly improve the continuity and signal-to-noise ratio of the high-order surface wave dispersion energy.

This invention discloses a miniaturized, ultra-wideband, dual-polarized antenna based on non-uniform planar loading, comprising a first layer, a second layer, and a third layer arranged sequentially from top to bottom. The first layer is a non-uniform planar structure composed of four types of elements, used to improve high-frequency beam splitting. The second layer is a radiator structure consisting of two pairs of orthogonally placed magnetoelectric dipoles. The third layer is a reflector cavity composed of a planar metal reflector and a vertically loaded metal plate. This invention discloses a miniaturized, ultra-wideband, dual-polarized antenna based on non-uniform planar loading. By using the non-uniform planar structure loaded at the top of the antenna radiator, the high-frequency anti-phase currents of the electric dipole arms are modulated into in-phase currents, suppressing higher-order modes and refocusing the split beam, thereby obtaining a stable, high-gain radiation pattern throughout the entire ultra-wideband frequency range.

This invention discloses a slow-wave structure and circuit suitable for high-order modes, including a housing, an upper gate extending from the top wall to the bottom wall of the housing, and a lower gate extending from the bottom wall to the top wall of the housing. Multiple upper and lower gates are staggered, defining multiple periodic vacuum cavities. The upper and lower gates have different heights along the height direction of the slow-wave structure. An electron beam channel is formed between the upper and lower gates. This invention can suppress low-order mode competition and back-wave oscillations at low operating voltages, achieving stable operation in high-order modes and achieving high output power of 100W or more with low voltage.

The invention discloses a compact arbitrary transverse mode laser. The laser comprises a pumping source, a pumping focusing optical system, a laser total reflective mirror, a laser gain medium, a laser output mirror and an astigmatism mode converter, the pumping source emits pumping light in a gain medium absorption band; the pump light is focused and then enters the gain medium; the gain medium absorbs the pump light and generates laser gain; the total reflective mirror highly reflecting laser wavelength and the output mirror partially transmitting the laser wavelength jointly form a simple linear resonant cavity. When the laser gain medium is inclined by a preset angle relative to the optical axis of the resonant cavity, meridian light and sagittal light pass through different optical paths of the gain medium to introduce astigmatism, an HG mode facing the directions of two astigmatism symmetry axes can be reproduced, and modes facing other directions cannot be reproduced due to the astigmatism effect. Therefore, when the pump light deviates from the axis of the resonant cavity in the directions of the two astigmatic symmetry axes, any high-order HG mode with mode ordinal numbers not being zero in the two directions can be excited, and any LG mode laser can be generated through astigmatic mode conversion.

The application discloses a few-mode fiber double-cascaded mode converter and a high-power few-mode fiber laser. A core base mode and a core high-order mode converter and a core high-order mode and a cladding mode converter are cascaded on the few-mode fiber. The refractive index modulation distribution of the core base mode and the core high-order mode converter is uniformly distributed in the core center, and is used for coupling the core base mode to the core high-order mode. The refractive index modulation distribution of the core high-order mode and the cladding mode converter is distributed at the junction of the core and the cladding, and is used for coupling the core high-order mode to the cladding to form loss. The few-mode fiber double-cascaded mode converter is connected before an output end cap of the high-power few-mode fiber laser, and can inhibit stimulated Raman scattering in the large-mode-field few-mode fiber laser, so as to improve the output performance of the fiber laser.

The utility model discloses a quasi single mode fiber with a large mode field effective area, which comprises a fiber core, an inner cladding, a ring core layer and an outer cladding, the fiber core is wrapped by the inner cladding, the inner cladding is wrapped by the ring core layer, the ring core layer is wrapped by the outer cladding, and the refractive index of the fiber core is larger than that of the inner cladding, the ring core layer and the outer cladding. The refractive index of the ring core layer is larger than that of the inner cladding and that of the outer cladding, and the refractive index of the inner cladding is equal to that of the outer cladding. According to the embodiment of the utility model, while the effective area of the optical fiber fundamental mode is increased, the coupling crosstalk between the fundamental mode and the high-order mode can be effectively suppressed, the communication power threshold of the optical fiber fundamental mode can be further increased on the premise of not adopting complex mode selective excitation, and the optical fiber can be widely applied to the technical field of optical communication.

The invention relates to a plano-concave laser resonant cavity and a method for generating high-order mode laser. The plano-concave laser resonant cavity comprises a resonant cavity body, a plane mirror and a concave mirror are arranged in the resonant cavity body, a strip-shaped non-reflection area is arranged in the middle of the reflecting surface of the plane mirror or the concave mirror, and a light absorption layer is arranged on the surface of the strip-shaped non-reflection area; the plane mirror and the concave mirror are both square lenses, the long side of the strip-shaped non-reflection area is parallel to one side of the plane mirror, or the projection of the long side of the strip-shaped non-reflection area in the main optical axis direction of the concave mirror is parallel to one side of the concave mirror; the method for generating the high-order mode laser comprises the steps that the plano-concave laser resonant cavity is adopted in the laser, the width of the strip-shaped non-reflection area is changed, and the laser emits Hermite-Gaussian TEM01, TEM04 and TEM05 laser respectively; the plano-concave laser resonant cavity not only can be used for generating high-order mode laser, but also is simple in structure and low in cost, and the output function of the method for generating the high-order mode laser is strong.

The invention discloses a surface wave frequency dispersion energy spectrum imaging method, system and device for improving F-K transformation resolution based on normalization preprocessing and a medium, and belongs to the technical field of surface wave exploration, and the method comprises the steps: collecting a plurality of seismic records of an acquisition domain; performing normalization preprocessing on the selected seismic record data to obtain preprocessed surface wave data; performing two-dimensional Fourier transform to obtain domain data, and transforming a domain into a domain according to the frequency dispersion characteristic of the surface wave data; and in the phase velocity range of the surface wave, determining a frequency dispersion curve recorded by the surface wave by selecting a peak point corresponding to any frequency in a domain. According to the method, by introducing a normalization preprocessing process, the comprehensive performance of a traditional F-K transformation method in surface wave frequency dispersion energy spectrum imaging is improved, the overall resolution of a frequency dispersion energy spectrum can be enhanced, the recognition capability of high-order mode frequency dispersion energy is improved, and energy spectrum distribution of a base order and a high-order mode is clearly separated.

Aspects of this disclosure relate to a bulk acoustic wave having a higher order mode as a main mode. The bulk acoustic wave device includes a frame structure in a frame region and a piezoelectric layer that has an engineered region in at least part of the frame region. Related acoustic wave filters, multiplexers, radio frequency modules, radio frequency systems, wireless communication devices, methods of manufacture, and methods of filtering are disclosed.

This invention discloses a high-efficiency nonlinear optical frequency converter based on high-power continuous optical transmission using quartz micro / nano fiber, comprising a wavelength-tunable laser, an optical fiber amplifier, a quartz micro / nano fiber, a sealed cavity, and an optical fiber low-pass filter; the quartz micro / nano fiber includes a first untapered portion, a second untapered portion, a first tapered transition region, a second tapered transition region, and a waist region, transmitting an optical field TE. 01 The mode cutoff method precisely controls the waist diameter of micro / nano fiber and accurately tunes the input light wavelength. The nonlinear light frequency conversion process excited by high-power continuous light transmitted in quartz micro / nano fiber satisfies perfect phase matching. The fundamental mode of the input light and the higher-order mode fields of the harmonic signal light have high overlap in the waveguide mode, which can efficiently generate continuous second and third harmonic signal light. The device has high stability, high efficiency, and low cost, and can be applied in fiber lasers, all-optical signal processing, fiber optic sensing and other fields.

Provided is an elastic wave device that improves resonance characteristics in a high-order mode. The elastic wave device comprises: a piezoelectric laminate having a first main surface and a second main surface on the opposite side from the first main surface in a first direction; an electrode provided on at least one among the first main surface and the second main surface of the piezoelectric laminate; and a support member provided on the second main surface side of the piezoelectric laminate and having an acoustic reflection part on the second main surface side of the piezoelectric laminate. At least a portion of the electrode is disposed so as to overlap the acoustic reflection part in a plan view in the first direction. The piezoelectric laminate comprises: a first piezoelectric layer having the second main surface; an intermediate layer laminated on the first piezoelectric layer; and a second piezoelectric layer laminated on the intermediate layer. At least one among the material and the polarization direction of the intermediate layer is different from that of the first piezoelectric layer. At least one among the material and the polarization direction of the intermediate layer is different from that of the second piezoelectric layer.

The application discloses an integrated tunable optical attenuator based on mode-circulating phase shift and reflection, comprising a single-mode optical waveguide, a 2*2 optical coupler, a high-order mode-circulating phase shifter and a waveguide optical reflector; wherein the 2*2 optical coupler is used for splitting the optical energy of the input port into two paths and outputting the optical energy into the high-order mode-circulating phase shifter, the high-order mode-circulating phase shifter uses the high-order mode selectivity of a mode coupler and the staggered arrangement of the mode order of a mode exchanger to make the optical field circulate in the high-order mode-circulating phase shifter for multiple times, thereby achieving the fold increase of the phase modulation efficiency; the waveguide optical reflector reversely couples the optical field modulated by the high-order mode-circulating phase shifter back to the high-order mode-circulating phase shifter, so that the optical field energy and information circulate in the high-order mode-circulating phase shifter for multiple times through the multimode optical phase shift arm, thereby further doubling the optical modulation efficiency.

The invention provides a chiral coupling ytterbium-doped optical fiber and a high-power optical fiber laser, and relates to the technical field of optical fibers. The ytterbium-doped optical fiber sequentially comprises a central fiber core, a plurality of spiral side cores, an inner cladding and an outer cladding from inside to outside, wherein the spiral side cores are spirally wound on the central fiber core along the axial direction of the central fiber core; wherein the basic mode refractive index of at least one spiral side core in the multiple spiral side cores is different from the refractive index of the central fiber core in a preset high-order mode, and the thermo-optical coefficient of the spiral side core with the refractive index different from the refractive index of the central fiber core in the preset high-order mode is larger than that of the central fiber core. The chiral coupling ytterbium-doped optical fiber provided by the invention can effectively remove a high-order mode in the central fiber core.

The invention discloses a high-power grating carrier optical fiber and a preparation method thereof, and relates to the technical field of laser manufacturing equipment. The high-power grating carrier optical fiber comprises a fiber core, and an inner cladding, a quartz outer cladding and an organic resin coating which are sequentially sleeved on the surface of the fiber core, the fiber core is composed of a core layer with a concave central refractive index and a germanium-doped core layer which is sleeved on the core layer with the concave central refractive index and is concentric with the core layer. And the inner cladding consists of five layers of refractive index modulated germanium-fluorine-doped quartz claddings of which the refractive indexes are alternated from high to low. The high-power grating carrier optical fiber not only has good photosensitivity and does not need hydrogen-loading sensitization, but also can inhibit different high-order modes to different extents under different wavelengths, effectively solves the problem that the endurance capacity is reduced due to heating of the carrier optical fiber in a laser working state, and improves the stability of the high-power grating carrier optical fiber due to regulation and control of a mode coupling state. And the output beam quality of the laser is greatly improved.

The polarization filtering structure comprises a section of tapering waveguide and at least one bent waveguide, a mode hybridization effect is generated in the tapering waveguide, a TM fundamental mode in the tapering waveguide is converted into a TE1 mode, the bent waveguide filters the TE1 mode, and only a TE fundamental mode is left; the intensity of the mode hybridization effect is evaluated according to an intensity coefficient k, the larger the k value is, the more obvious the mode hybridization effect is, and the shorter the required tapering waveguide length is. The invention has the advantages that the TM mode in the waveguide is converted into the TE1 mode through the tapering structure of the waveguide by utilizing the mode hybridization effect in the tapering waveguide, and the TE1 mode and other high-order modes with the same polarization are filtered out by connecting a plurality of bent waveguide structures, so that only the TE fundamental mode is ensured in the waveguide.

The invention provides a silicon photon gyroscope with a film-coated mode filtering double-Y waveguide integrated structure. The silicon photon gyroscope comprises a laser, a detector, a symmetrical double-Y waveguide, a first filter, a second filter, a third filter, a fourth filter, a first phase modulator, a second phase modulator and a ring, symmetrical optimization design is adopted for the symmetrical double-Y waveguides, namely mode excitation is reduced by conducting collaborative optimization on the front Y waveguide and the rear Y waveguide, the bifurcation angle of the front Y waveguide and the rear Y waveguide is controlled to be 8-12 degrees, the high-order mode excitation rate is controlled to be within 1%, and therefore space radiation mode errors and zero drift are remarkably reduced. A high-order mode excited in the beam splitting process is suppressed through the first and second filters, and a new mode of temperature gradient or stress introduction is prevented through the third and fourth filters; selective suppression of a high-order spatial mode is realized by adopting the filter with a film-coated structure, and meanwhile, low-loss transmission of a fundamental mode is kept, so that the zero-bias stability and the measurement precision of the silicon photon gyroscope are remarkably improved.

An optical waveguide device that can efficiently remove a high-order mode light beam and that is also easily manufactured even in a case where a width or a height of an optical waveguide is small is provided. An optical waveguide device includes a substrate 1 on which a rib type optical waveguide 10 is formed, and a slab waveguide SW disposed close to the rib type optical waveguide 10, in which roughness of at least a part (SF1) of an upper surface of the slab waveguide SW is larger than roughness (SF0) of a surface of a top portion of the rib type optical waveguide.

The application provides an array antenna and a communication device. The antenna unit of the array antenna comprises a first antenna and a second antenna. The working mode of the first antenna comprises a high-order mode of a first polarization mode and a high-order mode of a second polarization mode, and the working mode of the second antenna comprises a main mode of the first polarization mode and a main mode of the second polarization mode. In this way, by controlling the first antenna and the second antenna to jointly receive signals or transmit signals, the gain of the first antenna in the high-order mode and the gain of the second antenna in the main mode can be combined with each other, which is beneficial to reducing the gain of the grating lobe generated by the array corresponding to the plurality of second antennas when the array works in the main mode, thereby increasing the spacing between the antennas in the array antenna while ensuring the communication performance of the array antenna, and further reducing the layout difficulty of components in the array antenna supporting polarization reconstruction and improving the performance of the array antenna in the polarization reconstruction process.

The invention discloses a multi-band common orthogonal head, and belongs to the technical field of microwave communication. The invention discloses a four-way symmetrical waveguide filter which comprises an axial multi-frequency shared waveguide assembly and four side wall branch waveguides, the axial multi-frequency shared waveguide assembly comprises a coupling waveguide, a corrugated groove gasket and a high-frequency waveguide, the side wall branch waveguides are uniformly distributed in a four-way symmetrical mode relative to the multi-frequency shared waveguide assembly, and each side wall branch waveguide comprises an evanescent mode filter and an impedance conversion section. The antenna has the advantages of being large in bandwidth, small in frequency band interval, compact in structure and easy to machine. According to the invention, the problems of mixed-mode suppression, small-frequency-band interval electrical design and difficult processing of a millimeter wave band structure during ultra-wideband use are solved, the influence of a high-order mode on a directional diagram of a feed source system can be effectively improved, the cross polarization of the antenna is reduced, and the antenna is suitable for engineering popularization.

The present application relates to the field of microelectronic technology, and particularly relates to a low-loss elastic wave device and a communication device. The low-loss elastic wave device comprises a piezoelectric film, a top electrode, a pair of interdigital electrodes, a first bus bar, a second bus bar, a plurality of reflection grating electrodes and a reflection grating bus bar, the ends of a plurality of first interdigital electrodes and second interdigital electrodes in the pair of interdigital electrodes form a first end track and a second end track respectively, and the absolute value of the included angle γ between the track tangent of the first end track or the second end track at the end position of any corresponding interdigital electrode and the group velocity direction is greater than or equal to 16°, and the false finger length D of at least one false interdigital electrode is greater than or equal to 2λ, wherein λ is the center distance between adjacent interdigital electrodes on the same bus bar. The present application maintains the low loss of the device without increasing the device area by using a large included angle to suppress longitudinal high-order modes.

A two-dimensional photonic crystal surface-emission laser (10) includes a two-dimensional photonic crystal layer (12) formed by periodically arranging, in a plate-shaped base material (121), a different-refractive-index region (122) having a different refractive index from that of the base material (121); an active layer (11) provided on one surface side of the two-dimensional photonic crystal layer (12); and a reflection layer (15) provided on the other surface side of the two-dimensional photonic crystal layer (12) in a manner separated from the two-dimensional photonic crystal layer (12) or on the side of the active layer (11) opposite to the two-dimensional photonic crystal layer (12), wherein a distance d between the surfaces of the two-dimensional photonic crystal layer (12) and the reflection layer (15) facing each other is set so that a radiation coefficient difference Δα v =(α v1 ‑α v0 ) is 1 cm ‑1 or more, where α v is a radiation coefficient of a first high-order mode having the second smallest loss among the light amplified by the two-dimensional photonic crystal layer (12), and α v1 is a radiation coefficient of a fundamental mode having the smallest loss. v0 ​

The invention provides an all-optical switching device based on a PPy thin layer and a preparation method thereof, the switching device comprises a substrate layer, a straight waveguide core layer and a cladding, and the straight waveguide core layer structurally comprises an inorganic material, the PPy thin layer and a polymer material. The method comprises the step of burying a PPy thin layer in the center position of a straight waveguide core layer to modulate the refractive index of a polymer material and an inorganic material. The straight waveguide structure provided by the invention is simple in preparation method, small in structure size and easier to integrate. The PPy material has high thermal stability and excellent photo-thermal conversion efficiency, so that phases of three high-order modes of E12, E22 and E14 can be respectively regulated and controlled, and an all-optical switch function with low loss and quick response is realized.

This application provides a ring beam shaping system based on multimode fiber mode interferometry, comprising an input unit, a mode conversion unit, and an output unit. The input unit is a single-mode fiber with a first fiber parameter, used to input a Gaussian beam. The mode conversion unit is a multimode fiber with a second fiber parameter, connected to the single-mode fiber via fusion splicing, used to excite and interfere with higher-order modes. The output unit is a ring-core fiber with a third fiber parameter, connected to the mode conversion unit via fusion splicing, used to maintain and output a ring beam distribution. The core diameters of the single-mode fiber, multimode fiber, and ring-core fiber increase progressively, as do the NA values ​​of the single-mode fiber, multimode fiber, and ring-core fiber. This system achieves high-quality ring beam output through a simple, flexible, and efficient all-fiber structure, significantly reducing cost and complexity, improving stability and reliability, and has broad application prospects.

The present invention supports the implementation of structures for bulk acoustic wave resonators that can increase piezoelectric coupling and suppress parasitic modes. The grooves between the electrodes of the disclosed digital to analog converter (IDT) reduce the generation of parasitic modes and prevent the propagation of the parasitic modes and the resonance accumulation of the amplitude of the parasitic modes. In addition, the grooves between the disclosed IDT electrodes suppress a high order mode in a horizontal direction and increase the resonant-anti-resonant frequency gap of the bulk acoustic wave resonator.

This invention discloses a method and system for spectral characterization of few-mode fiber Bragg gratings based on lightweight adaptive control. The method includes: clarifying the multimode reflection characteristics and feedback mapping theoretical basis of the few-mode fiber Bragg grating; constructing an adaptive feedback closed-loop device containing the few-mode fiber Bragg grating based on the multimode reflection characteristics and feedback mapping theoretical basis; performing adaptive locking for different proportions of higher-order modes of the few-mode fiber Bragg grating through the adaptive feedback closed-loop device to characterize the evolution of the few-mode fiber Bragg grating and obtain a reflection spectrum dataset under different proportions of higher-order modes; and establishing a quantitative transfer matrix of the spectral characteristics and mode ratios of the few-mode fiber Bragg grating based on the reflection spectrum dataset.