221 results about "Higher order mode" patented technology

The invention provides a multi-mode hollow-core anti-resonance optical fiber, and relates to the technical field of optical fibers, and the multi-mode hollow-core anti-resonance optical fiber comprises a hollow outer layer tube and a plurality of cladding capillary tubes arranged on the inner wall of the outer layer tube; each cladding capillary tube comprises a circular tube, an elliptical tube and an anti-resonance plate, and the elliptical tube is nested in the circular tube through the anti-resonance plate and is coaxially arranged with the circular tube. In the technical scheme provided by the invention, the elliptical tube is nested in the circular tube by the anti-resonance plate, and the elliptical tube and the circular tube are coaxially arranged, so that a nested integrated cladding capillary tube is formed, and the multi-mode hollow-core anti-resonance optical fiber with the structure can reduce bending loss and limiting loss of the fiber core in a high-order mode.

A TE based on polymer optical waveguide 10 ‑TE 00 / TE 20 ‑TE 10 This compact mode converter belongs to the field of photonic integration technology. It consists of a substrate, a lower cladding, a core waveguide, and an upper cladding. The core waveguide is covered by the upper cladding. The lower and upper claddings are EpoClad, and the core waveguide is EpoCore, with the same height. It is constructed by sequentially connecting an input straight waveguide, a first intermediate asymmetric tapered waveguide, a second intermediate asymmetric tapered waveguide, a third intermediate asymmetric tapered waveguide, a fourth intermediate asymmetric tapered waveguide, a fifth intermediate asymmetric tapered waveguide, an output symmetric tapered waveguide, and an output straight waveguide. When passing through the intermediate asymmetric tapered waveguide, different mode components propagate with different effective lengths, causing different phase changes, ultimately resulting in the target mode. This increases channel transmission capacity and can be used in mode add / drop multiplexers (MADMs) and high-order mode filters.

Apparatuses and methods are provided for an optical frequency converter configured to double or have a carrier frequency of an input optical signal. The input optical signal provided to the optical frequency converter is a higher order mode than a mode of the output optical signal. The optical frequency converter comprises a core, cladding material, and a substrate. The core includes a first core portion of non-linear crystalline material which is non-centrosymmetric, and a second core portion and a third core portion of the non-linear crystalline material each of which is centrosymmetric. The first, the second, and the third core portions are coplanar with and adjacent to the first core portion between the second and the third core portions.

The invention relates to the technical field of laser beam shaping, discloses an active test method and system for a circuit breaker, and is used for solving the problem that the self-adaptive shaping capability of a CO2 laser beam is difficult to improve by the existing method. Firstly, a stable light path is constructed, and the stability of the light path is ensured through mechanical limiting, a thermal management module and multi-stage optical alignment; then low-power calibration is carried out, a deformable mirror initial driving table is generated through a least square inversion algorithm, and a flat-topped beam reference is established; data are collected through a wavefront sensor, a high-order mode is reconstructed, the voltage of a deformable mirror is dynamically refreshed, and wavefront control and scanning motion synchronization is ensured in combination with scanning galvanometer time sequence synchronization, closed-loop control and exception handling; monitoring the temperature of the deformable mirror, starting water-cooling adjustment, and correcting the driving table to cope with the heat effect; finally, a safety system is constructed, laser power, wavefront distortion and deformable mirror stroke parameters are monitored, dry gas purging is conducted on the diffractive optical element regularly, and safety guarantee and performance verification of the whole process are achieved.

The subject technology is related to acoustic resonators. More specifically, an embodiment of the subject technology provides an acoustic resonator device that includes a piezoelectric layer disposed between a first electrode and a second electrode. The total thickness of the first electrode, the second electrode, and the third electrode allows the device to operate according to a second (or higher order) thickness extension mode. There are other embodiments as well.

An optical device includes a transition unit in which a first waveguide and a second waveguide are disposed in an overlapped manner such that a magnitude relationship of an effective refractive index between the vertical modes propagating the first waveguide and the vertical modes propagating the second waveguide is inverted at the positions of input and output. The transition unit allows, at the input, the second waveguide to be a single mode waveguide and allows, at the output, the second waveguide to be a multi-mode waveguide through which TM0 light in the maximum vertical mode and light in a higher-order mode propagate. The optical device includes a removing unit that allows the second waveguide to be a single mode waveguide through which the TM0 light propagates by removing the light in the higher-order mode from the light received from the transition unit.

The invention provides a wide-ridge single-mode semiconductor laser and a manufacturing method thereof.The laser comprises an N electrode, a substrate layer, an epitaxial structure and a P electrode which are stacked in sequence, a grating layer is arranged in the epitaxial structure, and a grating is etched in the portion, close to the center, of the grating layer; the epitaxial structure is partially etched with the area where the grating is located as the center, a ridge-shaped structure is obtained, and the width of the ridge-shaped structure is larger than that of the grating. The grating is arranged in the epitaxial structure, and the high-order mode lasing of the wide-ridge semiconductor laser can be inhibited by regulating and controlling the feedback effect of the grating on different modes of the semiconductor laser, so that the quality of a fundamental mode beam is improved.

The invention relates to a transmitting / receiving arrangement (11) for a temperature-resistant radar-based level measuring device (1) which is designed for the efficient transmission and reception of radar signals (S HF1,2 , R HF1,2 ) in different frequency bands. For this purpose, the transmitting / receiving arrangement (11) is based on a waveguide (111), by means of which the temperature-sensitive high-frequency units of the level measuring device (1) are spaced from the possibly hot filling material (2). In this case, the radar signals (S HF1,2 , R HF1,2 ) are transmitted or received via the end region of the waveguide (111). According to the invention, the waveguide (111) has an internal cross-section (D) through which only the radar or reception signals (S HF1 , R HF1 ) of the lowest frequency band propagate exclusively in the fundamental mode, while the radar or reception signals (S HF2 , R HF2) of the higher frequency band must propagate predominantly in a higher-order mode. In order to ensure that all frequency bands are nevertheless transmitted at the end region with a common phase center and thus efficiently, a matching element (112) is arranged there according to the invention, which matches the radar signals (S HF2 ) of the high frequency band into lower modes in the direction of radiation. This design allows the transmit / receive arrangement (11) to be compact and efficient at the same time.

The invention provides an antenna system and a communication device, which can reduce the energy of grating lobes in an antenna array, is suitable for more scenes, and can be applied to communication scenes. The antenna system comprises a plurality of antenna units, and each antenna unit comprises a first antenna and a second antenna. The working mode of the first antenna comprises a high-order mode of a first frequency band, the working mode of the second antenna comprises a dominant mode of the first frequency band, and the first antenna and the second antenna are located in the same planar antenna array.

The invention discloses a GHz pulse train generation device and method, and relates to the technical field of laser, and the device comprises a seed light source, a first acousto-optic modulator, a 50: 50 coupler, an optical fiber loop, and a third acousto-optic modulator. Wherein the fiber loop comprises a second acousto-optic modulator, a first chirp long-period fiber grating, a polarization-maintaining double-clad fiber and a second chirp long-period fiber grating. By using the first chirp long-period fiber grating, the polarization-maintaining double-clad fiber and the second chirp long-period fiber grating, the dispersion effect in a fiber loop can be compensated, and the conversion rate of the chirp long-period fiber grating is relatively high, so that the transmission loss in the fiber loop can be reduced; group delay ripples of the chirp long-period fiber bragg grating and the optical fiber high-order LP0m mode are very low, the shape and the width of pulses in a GHz pulse string on a time domain can be controlled, and finally, the optical fiber of the chirp long-period fiber bragg grating is a polarization-maintaining double-clad optical fiber, so that the nonlinear effect can be effectively inhibited.

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.

The invention provides a controllable processing method for a photoetching single crystal optical fiber multi-ring cladding based on femtosecond laser and a multi-ring mask plate. The technical bottlenecks that in the prior art, the processing efficiency is low, the processing length is limited, and the structural precision is insufficient are effectively solved. The core of the method is that high-energy ultrashort pulse laser generated by a femtosecond laser is combined with a spatial light modulation technology of a programmable multi-ring mask plate to generate multi-layer femtosecond laser spots in specific annular distribution. Micron-scale focusing of multi-ring femtosecond laser beams can be achieved through a precisely-designed optical system, and precise spatial selective refractive index modulation is achieved on the cross section of the single-crystal optical fiber. Compared with a single-crystal optical fiber with a single-multi-ring annular cladding structure, the multi-ring annular cladding structure can further enhance the suppression capability of the multi-ring annular cladding structure on a high-order mode, realizes flexible regulation and control of a light wave transmission mode field, effectively reduces the influence of a multi-mode interference problem in the single-crystal optical fiber on the signal quality, and improves the signal quality. The stability of signal transmission and the quality of sensing signals are improved, and the application requirements of different scenes are met.

The present invention relates to the field microelectronic devices, and in particular to a surface acoustic wave resonator and a manufacturing method therefor, and a filter. The surface acoustic wave resonator comprises a support substrate, a functional layer, and an interdigital transducer which are sequentially arranged from bottom to top; the functional layer comprises a first dielectric region, a piezoelectric region, and a second dielectric region which are sequentially arranged in the first direction; a piezoelectric layer and a bottom electrode are arranged in an aperture region of the interdigital transducer, the width of the piezoelectric layer and the bottom electrode can be less than or equal to the width of the aperture region, the aperture region is a region where two types of oppositely arranged interdigital electrodes in the interdigital transducer are interlaced, and a target mode of the surface acoustic wave resonator is a high-order surface acoustic wave mode excited by a longitudinal electric field; and the product of the distance between adjacent first interdigital electrodes and the frequency of the target mode is less than the speed of sound of the support substrate, thereby avoiding parasitic bulk acoustic waves generated by excitation of the longitudinal electric field, and facilitating suppression of a transverse high-order mode.

The invention discloses an optical emission chip, an optical fiber and an optical signal transmission system, and belongs to the field of optical transmission. A light beam emitted by an emission laser can be divided into a first sub-light beam and a second sub-light beam through a first beam splitter; on one hand, the light field mode of the first sub-light beam is converted into a high-order mode and local oscillation light is obtained (so that the local oscillation light can be coupled to a coating layer of the optical fiber for transmission), and on the other hand, information to be transmitted is coupled to the second sub-light beam and signal light is obtained, so that the signal light is coupled to a fiber core of the optical fiber for transmission. And finally, the local oscillation light and the signal light are combined into a light beam to be transmitted by a first beam combiner, so that the light beam to be transmitted is transmitted to a receiving end through different layers of the optical fiber. On one hand, a receiving end does not need to be provided with a laser for generating local oscillation light, on the other hand, local oscillation light and signal light can be transmitted through a single optical fiber, and cost and hardware complexity of an optical transmission system can be reduced at the same time.

The invention provides a laser chip with a transverse carrier expansion superlattice and a preparation method, and relates to the technical field of semiconductor lasers. The chip sequentially comprises an N-type ohmic electrode, a substrate, a buffer layer, an N-type limiting layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type limiting layer, an ohmic contact layer and a P-type ohmic electrode. A first superlattice layer is inserted into the two sides of the P-type waveguide layer, wherein the first superlattice layer is formed by alternately overlapping an undoped and narrow-band-gap Al < x > < 7 > In < y > < 7 > Ga < 1-x > < 7-y > As layer and a P-type doped and wide-band-gap Al < x > < 8 > In < y > < 8 > Ga < 1-x > < 8-y > As layer. A second superlattice layer is inserted into the two sides of the P-type limiting layer, wherein the second superlattice layer is formed by alternately overlapping an undoped Al < x > < 10 > In < y > < 10 > Ga < 1-x > < 10-y > As layer with a narrow band gap and a P-type doped Al < x > < 11 > In < y > < 11 > Ga < 1-x > < 11-y > As layer with a wide band gap. The chip utilizes the first superlattice layer and the second superlattice layer to promote holes at two sides of a device to migrate and transport from two sides of the chip to the middle in the undoped narrow-band gap layer, large optical loss is not caused, high electro-optical conversion efficiency is ensured, the intensity of a fundamental mode is improved, and a high-order mode is inhibited.

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.

The invention discloses a square optical fiber curvature sensor and a knee joint angle monitoring system, and relates to the technical field of optical fiber sensing. The square optical fiber is used for replacing a traditional optical fiber with a circular cross section, and a square optical fiber light field is distributed in a rectangular shape, so that when a rectangular light spot is subjected to mode excitation, due to uniform energy of the rectangular light spot, a large amount of light on two sides of the light spot can be excited to a high-order mode to form interference, and the sensitivity of the sensor is improved; in addition, the square optical fiber is provided with an etching cavity to form a Fabry-Perot resonant cavity, so that the sensitivity of the sensor is further improved.

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 present application discloses a terahertz single-ridge waveguide bandpass filter based on high-order modes, comprising a metal waveguide with a hollow structure, a metal ridge structure arranged in the metal waveguide, and a plurality of perturbation metal pillars, wherein the bottom of the metal ridge structure is connected to the bottom inner wall of the metal waveguide, the top of the perturbation metal pillar is connected to the top inner wall of the metal waveguide, and the bottom of the perturbation metal pillar is spaced apart from the metal ridge structure. The RWG to SRW conversion structure and the ridge structure transition section are mirror-distributed between the input port and the output port of the filter with the SRW filter structure as the center. The present application adopts air filling to reduce loss and utilizes the high-order modes of the SRW filter structure for bandpass filtering. The selection of high-order modes ensures that the filter has a good bandpass response within the target frequency band, avoiding the size and performance limitations brought by low-order modes. The perturbation metal pillars can further improve the out-of-band suppression performance of the filter.

The invention discloses an active mode demultiplexing module which comprises a mode converter, two optical circulators and a bidirectional semiconductor optical amplifier. The mode converter is used for converting a high-order mode into a fundamental mode to complete primary mode demultiplexing, fundamental mode signals after primary demultiplexing are injected into the bidirectional semiconductor optical amplifier through the two optical circulators from the positive direction and the negative direction respectively, and the signals after being shaped by the bidirectional semiconductor optical amplifier are output by the corresponding optical circulators. A bidirectional symmetrical injection structure is formed, different propagation is beneficial to separation of different signals, and mutual interference, namely mode crosstalk, between forward and reverse signals can be effectively reduced, so that a mode demultiplexing function is better completed, and an output signal has higher signal quality than a primary demultiplexing signal. Besides, by optimizing and adjusting the driving current of the bidirectional semiconductor optical amplifier or an auxiliary optical pumping mode, not only can the gain of the mode channel be dynamically adjusted, but also the power balance of the mode channel and the demultiplexing of a high extinction ratio mode can be realized; the method is especially suitable for receiving few-mode signals in a mode division multiplexing (MDM) optical transmission system and constructing optical switching nodes in a multi-dimensional multiplexing optical network.

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.

The present invention discloses a compact waveguide duplexer for the W-band, comprising: a first dual-mode resonator connected to the waveguide input port, a second dual-mode resonator connected to the first waveguide output port, and a third dual-mode resonator connected to the second waveguide output port; the first dual-mode resonator is connected to the second dual-mode resonator through a first single-mode resonator and a second single-mode resonator operating in the first passband; the first dual-mode resonator is connected to the third dual-mode resonator through a third single-mode resonator and a fourth single-mode resonator operating in the second passband; the first to third dual-mode resonators are TE 301 / TE 102 -mode resonators; the first to fourth single-mode resonators are TE 101 -mode resonators. In the present invention, a dual-mode resonator based on a higher-order mode is used as a T-junction to connect the two passbands of the duplexer, reducing the footprint of the duplexer, improving the performance, having a simple structure, and being easily extended to higher frequency bands.

This invention discloses a microwave heating device with high-order mode suppression, belonging to the field of microwave heating technology. It includes: a heater comprising a rectangular waveguide and metal ridges; the rectangular waveguide has a microwave cavity extending laterally; two metal ridges are symmetrically arranged front-to-back within the microwave cavity, with a front-to-back spacing between them, and each ridge has a material passage hole extending front-to-back; and two high-order mode suppressors, respectively located at the front and rear ends of the heater, each high-order mode suppressor having a material cavity for the workpiece to be heated to pass through, extending front-to-back and communicating with the material passage hole. This invention features a compact structure, strong electric field, rapid and uniform heating, and protection against high-frequency radiation, preventing harm to operators from microwave spatial radiation and ensuring the safe use of the microwave heating device.

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 invention relates to the technical field of semiconductor lasers, in particular to a single-mode high-power surface-emitting semiconductor laser and a manufacturing method thereof. The laser comprises an N electrode layer, an epitaxial structure, an insulating layer and a P electrode from bottom to top, wherein the epitaxial structure comprises a substrate, an N-type DBR layer, a transition layer, an active region layer, a super-symmetric coupling cavity layer, an oxide layer and a P-type DBR layer; an unoxidized hole is formed in the center of the oxide layer, a gain cavity corresponding to the unoxidized hole is formed in the super-symmetric coupling cavity layer, and a loss cavity is formed in the periphery of the gain cavity. The super-symmetric coupling cavity layer with the gain cavity and the loss cavity is arranged between the active region layer and the oxide layer, loss of an optical field in a high-order mode is limited in the loss cavity, the gain difference between a fundamental mode and the high-order mode is increased, stable single-mode output is achieved, and the output efficiency is improved. The technical problems that in a vibration exciter in the prior art, shallow layer etching on an epitaxial structure has limited high-order mode loss, and single-mode output performance and stability cannot be guaranteed are effectively solved.

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.