287 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.

The invention discloses a low-repetition-frequency spiral microcavity structure and a design method, and belongs to the field of silicon-based integrated photon chips. The low-repetition-frequency spiral microcavity structure comprises a first spiral bent waveguide, a second spiral bent waveguide, an internal connection bent waveguide, an external connection bent waveguide and a bus waveguide. The curvature radius of each point of the internal connection bending waveguide changes along with the length and meets the Euler spiral equation, and the internal connection bending waveguide is used for connecting the starting points of the first spiral bending waveguide and the second spiral bending waveguide. The external connection bending waveguide is used for connecting the end points of the first spiral bending waveguide and the second spiral bending waveguide. The first spiral bent waveguide, the second spiral bent waveguide, the internal connection bent waveguide and the external connection bent waveguide form a closed spiral annular waveguide. A light beam transmitted in the bus waveguide is coupled into the spiral annular waveguide. The invention further discloses a design method of the low-repetition-frequency spiral microcavity structure. According to the invention, loss caused by high-order mode crosstalk and mode mismatch can be reduced, and the area utilization rate of a chip is improved.

The invention relates to a flexible planar transmission line for communication between a first electronic device and a second electronic device. The flexible planar transmission line comprises a first conducting layer, a dielectric layer, a second conducting layer, a signal line provided in the dielectric layer and a concatenation of a first filter and a second filter, wherein the first filter being arranged to attenuate frequency components of a signal and a second filter being arranged to attenuate higher order modes of the propagated signal.

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 discloses a polarization rotation beam splitter structure based on a lithium niobate film, belongs to the technical field of optical waveguides, and particularly relates to an integrated optical device for realizing polarization rotation and beam splitting of optical signals. The main structure is two linear tapered waveguides and an asymmetric coupler, the structure utilizes the excellent electro-optical characteristics of a lithium niobate film, and through the design of the linear tapered waveguides and an asymmetric directional coupling unit, when light is transmitted along the tapered waveguides which are gradually increased, due to the hybridization between modes, the light transmission efficiency is improved, and the light transmission efficiency is improved. The TM0 mode of narrow band import emission is gradually converted into the high-order TE1 mode, the high-order TE1 mode is coupled through the asymmetric coupler and converted into the TE0 mode to be output, efficient polarization rotation and beam splitting functions between the TM mode and the TE mode are achieved, and potential application prospects are achieved. The polarization rotation beam splitter not only realizes simplification of a device structure, is expected to be applied to efficient polarization multiplexing and polarization modulation, but also provides flexibility for manufacturing a large-scale optical switch array and an optical interconnection network.

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 invention provides a multi-mode hollow-core anti-resonance optical fiber. The multi-mode hollow-core anti-resonance optical fiber comprises a tubular outer wrapping layer, an inner wrapping layer and an outer wrapping layer, the plurality of tubular anti-resonance structures are uniformly distributed on the inner wall of the outer cladding; the anti-resonance structure comprises at least two tubular sub-anti-resonance structures which are nested in sequence; in the same anti-resonance structure, the sub-anti-resonance structure on the innermost layer is tangent to the inner wall of the outer cladding layer, the tubular side wall of at least the sub-anti-resonance structure on the outermost layer is provided with an opening extending in the length direction, and the opening is fixed to the inner wall of the outer cladding layer. The anti-resonance structure formed by the at least two tubular sub-anti-resonance structures which are sequentially nested can form a multi-layer anti-resonance reflection interface, the leakage of a fundamental mode and a high-order mode of the optical fiber is limited, the transmission loss is reduced, the sub-anti-resonance structure on the innermost layer is tangent to the inner wall of the outer cladding layer, and a tangent point is formed. And the tangent point is not in contact with the intersection point of the opening fixed on the inner wall of the outer cladding, so that a flatter broadband transmission spectrum is provided for the optical fiber.

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 discloses a broadband low-profile circularly polarized dielectric resonator antenna. The antenna comprises a first dielectric substrate, a second dielectric substrate and a third dielectric substrate, wherein the first dielectric substrate is provided with a microstrip slot coupling feed unit; the dielectric resonator is arranged on the first dielectric substrate, four corners of the dielectric resonator are respectively provided with an angle block, and the angle blocks are arranged in a central symmetry manner by taking the center of the dielectric resonator as a symmetric center; second dielectric substrates are arranged on angle blocks of the dielectric resonators, and parasitic metal strips are arranged between the second dielectric substrates and the dielectric resonators. Through the combination of the feed coupling slot mode, the basic mode of the dielectric resonator and the third high-order mode, the impedance and the axial ratio bandwidth are effectively expanded. And through the parasitic metal strip and the selection of the aluminum oxide ceramic material without surface loss and the resonator structure, the gain is remarkably improved, the profile height of the antenna is reduced, and the radiation efficiency of the antenna is improved.

The invention discloses an annular fiber grating manufacturing method and system for a high-order mode coupling fundamental mode, and the method comprises the steps: starting a femtosecond laser and corresponding equipment, and enabling the femtosecond laser and corresponding equipment to be in a standby state, so as to guarantee the stability of laser processing; a coating layer at the optical fiber processing position is stripped, the relative distance and height of the electric rotating clamps on the two sides are adjusted, so that the exposed part of the optical fiber is located between the electric rotating clamps on the two sides, and the horizontal and vertical positions of the electric displacement platform are adjusted; the grating period lambda, the rotating speed of the electric rotating clamp, the moving speed of the electric displacement platform, the interval time of opening and closing of the laser valve and the period number are preset on the computer; and executing a preset program, and forming annular fiber gratings periodically distributed along the fiber axis on the interface of the fiber core and the cladding. The annular fiber bragg grating inscribed by the method has circular symmetry performance, and the problem that mode coupling is influenced by random azimuth angles of a transverse mode field in a high-order mode influenced by non-uniform fiber refractive index distribution and external environment disturbance can be effectively avoided.

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 relates to the technical field of semiconductor lasers, in particular to a metasurface unit, a semiconductor laser and a preparation method. The metasurface unit comprises a first column body and a second column body, wherein the first column body and the second column body are sequentially arranged from bottom to top; wherein the first column body is a rectangular photonic crystal column, and the rectangular photonic crystal column is used for suppressing radial and angular high-order modes of output light; the tubular column is used for further controlling the light beam of the output light, so that the single-mode output efficiency of the output light is improved. According to the embodiment, radial and angular high-order modes of output light can be effectively suppressed through the diffraction characteristic of the rectangular-column photonic crystal. And the super lens formed by the tubular column is arranged on the rectangular column, the focusing capability of the super lens is utilized to further improve the beam quality, and the gradient design of the curvature radius of the lens enables beam behaviors in different areas to be accurately controlled.

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 provides a sound wave resonator, a preparation method thereof and a filter, and aims at sound waves with strong dispersion characteristics in a target mode, the influence of the thickness of a piezoelectric film on sound velocity far exceeds the duty ratio 2W / lambda of an interdigital transducer electrode. The thickness of a piezoelectric film corresponding to the lower part from a certain area at the tail end of an electrode finger overlapping area of the interdigital transducer to the tail end part of a bus bar is increased, so that the thickness of the piezoelectric film is thicker than that of a piezoelectric film corresponding to the middle part of the electrode finger overlapping area; therefore, the sound velocity of the target mode in the piezoelectric film in the thicker area is lower than the sound velocity of the target mode in the piezoelectric film in the thinner area, so that the transverse high-order mode is effectively inhibited, and the performance of the device is improved. Besides, the structure can suppress the transverse high-order mode only by increasing the thickness of the partial area of the piezoelectric film, the structure is simple, the preparation is easy, the requirement on the process precision is low, and the process complexity and the manufacturing cost can be effectively reduced on the premise of effectively ensuring the performance of the resonator.

The invention discloses an on-chip integrated laser source and a preparation method thereof. According to the on-chip erbium-doped laser source, tantalum oxide doped with rare earth ions serves as a gain dielectric layer, tantalum oxide not doped with rare earth ions serves as a waveguide layer to be deposited on the gain dielectric layer to form a double-layer thin film structure, and then an Euler bent micro-ring resonant cavity structure is designed and prepared on the undoped layer. Compared with a conventional micro-ring resonant cavity prepared on a rare earth doped film, the Euler micro-ring designed in the invention not only can reduce scattering loss and high-order mode crosstalk in a wide waveguide, but also can avoid roughness caused by conventional direct etching of a rare earth ion doped film layer.

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.

A single-mode high-nonlinearity photonic crystal fiber capable of maintaining circular polarization transmission comprises a solid fiber core and a porous cladding structure arranged periodically, and the nonlinearity of the fiber is improved by optimizing the size of the fiber core and the duty ratio of cladding air holes. The torsion rate alpha introduced in the axial direction of the optical fiber is 0-8 rad / mm to introduce 10 <-3 >-order circular birefringence to maintain the circular polarization state, and effective refractive index change curves in different modes are changed. A plurality of cladding air holes are selected on the cross section of the optical fiber for selective filling or doping to realize phase matching of a fiber core high-order mode and a plurality of cladding modes, so that the fiber core high-order mode with the refractive index changing under torsion is filtered out by means of intermode coupling, the loss of the filtered high-order mode is increased by more than two orders of magnitude, and the high-order mode loss is reduced by more than two orders of magnitude. And single-mode transmission is effectively realized. Meanwhile, the characteristics of circular polarization state transmission and high nonlinearity are kept, and the optical fiber can be applied to application research of high-precision optical fiber sensing, optical fiber lasers with special circular polarization state output and the like.

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 high-order mode filter and a preparation method thereof. The high-order mode filter comprises a substrate, a flat plate groove, a first stray light absorption region and a reflection region, wherein the substrate comprises a base, an insulating layer and a semiconductor top layer which are arranged in sequence; the flat plate grooves are arranged in the semiconductor top layer at intervals, and a ridge waveguide is formed between every two adjacent flat plate grooves; the first stray light absorption areas are distributed in the semiconductor top layer on the two sides of the ridge waveguide and are used for absorbing stray light in incident light; the reflection areas are arranged in the flat plate grooves in the two sides of the ridge waveguide, an inclination angle is formed between the length direction of the reflection areas and the light propagation direction in the ridge waveguide, the inclination angle is smaller than 90 degrees, and the reflection areas are used for reflecting light emitted from the outer sides of the reflection areas to the ridge waveguide. The stray light reflected by the side wall of the flat plate groove can be blocked to a great extent, the stray light is prevented from entering the waveguide again, and attenuation of stray light is greatly increased.

The invention provides a lateral composite photonic crystal semiconductor laser which can be applied to the technical field of artificial micro-nano structures and semiconductor lasers. The laser comprises a gain main array etched on an epitaxial structure, a loss lateral photonic crystal array and an additional microstructure, and the loss lateral photonic crystal array is located on at least one side of the gain main array; the additional microstructure is located on at least one side of at least one of the gain main array and the loss lateral photonic crystal array. A loss lateral photonic crystal array of a known gain main array is constructed through scanning matching of a transmission matrix method, and the loss lateral photonic crystal array and the loss lateral photonic crystal array are mutually coupled, so that the mode discrimination capability between a fundamental mode and a high-order mode of the laser is improved while the loss of a high-order side mode is improved, and single-mode laser output with the fundamental side mode as the main mode is obtained. The horizontal far-field divergence angle of the laser is reduced, and the lateral beam quality of the laser is improved.

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.