In this paper, a novel method of a subwavelength binary simple periodic rectangular structure is presented to realize even beam splitting by combining the rigorous couple-wave analysis with the genetic algorithm. Seve...In this paper, a novel method of a subwavelength binary simple periodic rectangular structure is presented to realize even beam splitting by combining the rigorous couple-wave analysis with the genetic algorithm. Several even splitters in the terahertz region were designed and one of the silicon-based beam splitters designed to separate one incident beam into four emergent beams has total efficiency up to 92.23 %. Zero-order diffraction efficiency was reduced to less than 0.192 % and the error of uniformity decreased to 6.51 9 10-6. These results break the limitation of even beam splitting based on the traditional scalar theory. In addition, the effects of the incident angle, wavelength, as well as the polarizing angle on the diffraction efficiency and uniformity were also investigated.展开更多
In turbomachinery,strong secondary flow can produce significant losses of total pressure near the endwall and reduce the efficiency of the considered turbomachine.In this study,splitters located at different positions...In turbomachinery,strong secondary flow can produce significant losses of total pressure near the endwall and reduce the efficiency of the considered turbomachine.In this study,splitters located at different positions with respect to the main blade have been used to reduce such losses and improve the efficiency of the outlet guide vane(OGV).Three different relative positions have been considered assuming a NACA 65-010 profile for both the main blade and the splitter.The numerical results indicate that splitters can effectively reduce the total pressure loss by suppressing the secondary flow around the main blade,but the splitters themselves also produce flow losses,which are caused by flow separation effects.展开更多
We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entan...We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entangled optical states.Indeed,the decoherence effect is exploited positively here to generate such kind of quantum channels.Next,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.展开更多
In this paper, we construct photon-added f-deformed coherent states （PAf-DCSs） for nonlinear bosonic fields by discussing Klauder＇s minimal set of conditions required to obtain coherent states. Using this set of no...In this paper, we construct photon-added f-deformed coherent states （PAf-DCSs） for nonlinear bosonic fields by discussing Klauder＇s minimal set of conditions required to obtain coherent states. Using this set of nonlinear states, we propose a very useful scheme for generating the maximal amount of entanglement via unitary beam splitters for different strength regimes of the input field α, deformation q and excitation number m. Therefore, the possibility to create highly entangled states and to control the entanglement is proposed. Moreover, the condition for a maximal and separable output beam state is obtained. Finally, we examine the statistical properties of the PAf-DCSs through the Mandel parameter and exploit a connection between this quantity and the behavior variation of the output state entanglement. Our result may open new perspectives in different tasks of quantum information processing.展开更多
An initial structure design of MMI 1×8 optical power splitters is reported.The waveguide material is Si-based SiO2 Ge-doped and deposited by PECVD method.Embedded strip structure is implied in the section design....An initial structure design of MMI 1×8 optical power splitters is reported.The waveguide material is Si-based SiO2 Ge-doped and deposited by PECVD method.Embedded strip structure is implied in the section design.By using BPM-CAD,a favorable result is obtained that this device has a sound uniformity and fairly low loss.Meanwhile,simulations of designs with certain changed parameters is also implemented for a better design configuration.展开更多
The production of maxima and minima by the superposition of two or more light signals provides fundamental support for the wave nature of light. This result is based on the study of wave interference phenomena which r...The production of maxima and minima by the superposition of two or more light signals provides fundamental support for the wave nature of light. This result is based on the study of wave interference phenomena which remains the only approach to explain the production of those maxima and minima. In a system that is prepared to work with only one photon at a time, any detector can signal only one or zero. In 1986, a rigorously controlled experiment was designed by Grangier, G. Roger, and A. Aspect, [Europhys Lett. 1(4), p. 173, 1986] that guaranteed a single-photon beam. The explanation of the experimental results implied the interference of the wave function of a single-photon with itself. Thus, the explanation of interference that is accepted for an ensemble of photons was assumed to be valid for a single photon. In this study, we prepare a Mach-Zehnder interferometer using the same type of beam splitters used by Grangier et al. to test the assumption mentioned above. Our results allow us to explain the results of Grangier et al. because of the interaction between light and the beam splitters. Our results also verify that their wave interpretation of the results is not valid. Here, we present the essential findings of the extensive experimental evidence that supports our ideas.展开更多
In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can p...In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can permanently store the image and instantaneously generate its corresponding optical signals has been proposed.In this framework,an original image is sliced into non-overlapping sub-images,each of which contains 3 pixel×3 pixel or 5 pixel×5 pixel,and these subimages are respectively stored in storage units,which are nine-channel or 25-channel power splitters(PSs).The gray values of pixels in each sub-image are sequentially mapped to the light intensity of channels in each PS.These PSs are inversely designed by combining the adjoint method(AM)and the finite-difference frequency-domain method.Using this method,high-performance memory has been realized based on PSs,with a maximum 33.37 dB signal-to-noise ratio.Using multiobjective AM,the storage capacity has been doubled according to the working wavelengths.For example,two sub-images with pixels arranged as‘T'and‘L'shapes can be retrieved at 1310 and 1550 nm,respectively.This framework provides highly stable,non-volatile image storage,and instantaneous generation of optical signals for future all-optical computing systems.展开更多
The beam splitter is one of the most crucial components in optical and electromagnetic systems,and it is also expected to be applied in terahertz(THz)technology.However,most existing beam splitters operate in only a s...The beam splitter is one of the most crucial components in optical and electromagnetic systems,and it is also expected to be applied in terahertz(THz)technology.However,most existing beam splitters operate in only a single working mode,restricting their applications.This paper reports a method for the inverse design of a doublet meta-device consisting of two stacked metasurfaces functioning as a reconfigurable THz beam splitter.It is made of photo-curable high-temperature resin using 3D printing technology.By simply adjusting the relative rotation angles between the two metasurfaces to 0°,90°,180°,and 270°,the meta-device can produce four distinct focal patterns,thus achieving four different working modes.This scheme avoids introducing complicated active components,offering a simple,low-cost design of a signal divider in future 6G THz communication systems.展开更多
To enhance the efficiency of wind energy harvesters,aerodynamic modifications to bluff bodies prove highly effective.This study introduces two innovative galloping piezoelectric energy harvesters(GPEHs)equipped with t...To enhance the efficiency of wind energy harvesters,aerodynamic modifications to bluff bodies prove highly effective.This study introduces two innovative galloping piezoelectric energy harvesters(GPEHs)equipped with two symmetrical splitters on a cuboid bluff body:GPEH with upstream splitters(GPEH-US)and GPEH with downstream splitters(GPEH-DS).Wind tunnel experiments evaluated the impact of splitter angle and length on energy harvesting performance across varying wind speeds.The results indicate that larger splitter angles and shorter lengths are more favorable for energy harvesting in GPEH-US.The optimal configuration,determined as GPEH-US with α=90°,L=0.4D,reduces the threshold wind speed,expands the effective wind speed range for energy harvesting,and increases maximum voltage and power output by over 99%,301%,respectively,compared with conventional GPEH.Conversely,GPEH-DS are less effective for energy harvesting but demonstrate potential in vibration control applications.Computational fluid dynamics(CFD)simulations using the OpenFOAM toolbox qualitatively elucidate the physical mechanisms driving these results.A larger splitter angle enables secondary small-scale vortices(SV)to absorb more energy,accelerates boundary layer separation,intensifies and disorderly vortex shedding,enhances aerodynamic instability,and improves energy harvesting performance.展开更多
We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured i...We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured insertion losses(ILs)of the three-channel and dual-mode waveguide crossing(WC)for both the fundamental transverse electric(TE0)and TE1 modes are less than 1.8 dB or 1.9 dB from 1540 nm to 1560 nm.At the same time,the crosstalks(CTs)are lower than-17.4 dB or-18.2 dB.The consistent test results indicate the accuracy of the(W)PS-based testing circuit.Additionally,combining the tunable tap couplers,the(W)PS can provide multiple testing points with different modes and different transmittances.展开更多
Separating lights into different, paths according to the polarization states while keeping their respective path's polarizations with high purification is keen for polarization multiplex in optical communications....Separating lights into different, paths according to the polarization states while keeping their respective path's polarizations with high purification is keen for polarization multiplex in optical communications. Metallic nanowire gratings with multi-slits in a period are proposed to achieve polarized beam splitters (PBSs) in reflection and diffraction. The setting of multi-slits largely reduces the reflection of photons with a transverse magnetific field via the plasmonic waveguiding effect, which leads to highly polarized output lights with extinction ratio larger than 20 dB in each channel. The proposed reflection/diffraction PBSs enrich the approaches to control the polarization states with the advantages of wide incident angles and flexible beam splitting angles.展开更多
Two types of 1×2 multi-mode interference （MMI） splitters with splitting ratios of 85：15 and 72：28 are designed. On the basis of a numerical simulation, an optimal length of the MMI section is obtained. Subseq...Two types of 1×2 multi-mode interference （MMI） splitters with splitting ratios of 85：15 and 72：28 are designed. On the basis of a numerical simulation, an optimal length of the MMI section is obtained. Subsequently, the devices are fabricated and tested. The footprints of the rectangular MMI regions are only 3×18.2 and 3×14.3 （#m）. The minimum excess losses are 1.4 and 1.1 dB. The results of the test on the splitting ratios are consistent with designed values. The devices can be applied in ultra-compact photonic integrated circuits to realize the ＂tap＂ function.展开更多
To simultaneously reduce flow-induced noise and enhance hydraulic performance in centrifugal pumps,this study proposes a bionic volute tongue inspired by the serrated trailing-edge morphology of the long-eared owl win...To simultaneously reduce flow-induced noise and enhance hydraulic performance in centrifugal pumps,this study proposes a bionic volute tongue inspired by the serrated trailing-edge morphology of the long-eared owl wing.Hydraulic performance and volute-induced noise are integrated into a unified evaluation framework,enabling multi-objective optimization of the tongue geometry.An orthogonal experimental design coupled with Computational Fluid Dynamics(CFD)and Computational Fluid Acoustics(CFA)is employed to systematically assess the influence of serration parameters.A matrix-based decision method is then used to identify the optimal configuration balancing efficiency,head,and acoustic performance.The optimized design reduces the area fraction of extremely high-velocity regions(>18 m/s)from 15.21% to 5.38%,corresponding to a 64.63% decrease,while the flow non-uniformity coefficientζis reduced by 26.1%.Under rated operating conditions,the pump head increases by 0.5 m,hydraulic efficiency improves by 5%,and volute-induced noise is reduced by approximately 5 dB.Flow-field analysis indicates that volute-induced noise is the dominant source of hydrodynamic noise,and that the serrated bionic tongue effectively suppresses its intensity.The noise reduction mechanism is attributed to improved rotor-stator interaction,decomposition of large-scale vortical structures,and delayed flow separation,which collectively reduce pressure pulsation at the rotor-stator interface.展开更多
We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semicon...We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semiconductor lasers,as well as Raman and semiconductor optical amplifiers.Although inverse design approaches for optical detectors remain relatively underexplored,we examine optical layers,particularly metamaterial absorbers,as promising candidates for high-performance optical detection.In addition,we underscore advancements in inverse designing passive optical components,including beam splitters,gratings,and optical fibers.These optical blocks are fundamental in developing next-generation standalone optical communication systems and optical sensing networks,including integrated sensing and communication technologies.While categorizing various reported deep learning architectures across five paradigms,we offer a paradigm-based perspective that reveals how different ML techniques function within modern inverse design methods and enable fast,data-driven solutions that significantly reduce design time and computational demands compared with traditional optimization methods.展开更多
This paper describes the optimization of the impeller having splitters for a turbo blower.Two design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower performance.Blower pressure a...This paper describes the optimization of the impeller having splitters for a turbo blower.Two design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower performance.Blower pressure and ef-ficiency are selected as an object function,and the optimization of the blower impeller is performed by a response surface method (RSM).Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each case.Throughout the shape optimization of the splitters attached to the impeller in the turbo blower,pressure and efficiency at the design flow condition are suc-cessively increased by 5.9 percent and 17.9 percent respectively based on the reference blower.The higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of im-peller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference blower.For the object function of pressure,pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference blower.The enhancement of blow-er performance is due to the reduction of reverse and circulation flows in the blade passage.展开更多
The soft X-ray interferometry is completed by the Mach-Zehnder interferometer using a soft X-ray laser, and it is also an important method to measure the electron densities of a laser-produced plasma near the critical...The soft X-ray interferometry is completed by the Mach-Zehnder interferometer using a soft X-ray laser, and it is also an important method to measure the electron densities of a laser-produced plasma near the critical surface. It is apparently demonstrated in this paper that the incident angle of each optical element in the soft X-ray Mach- Zehnder interferometer should be near normal incidence based on the polarized characteristics of the soft X-ray mul-tilayers, and the product of reflectivity and transmission of the beam splitter should be taken as a standard of design according to the structure of the soft X-ray Mach-Zehnder interferometer. The beam splitters used in the soft X-ray interferometry at 13.9 nm are fabricated using the ion beam sputtering. The figure error of the beam splitter has reached the nanometer magnitude, in which the product of reflectiv-ity and transmission of the beam splitter is more than 1.6%.展开更多
In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on p...In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on power splitting ratios are investigated in detail and the corresponding output intensities as functions of the relative positions in the numerical simulation are plotted,which are in good accordance with the experimental results.In addition,the waveguide beam splitter with a 1:1:1 splitting ratio is fabricated by changing the relative widths of the three branch-waveguides.Guiding performances at 532 nm are measured and analyzed by a typical end-face coupling system.The simulation and experimental results demonstrate that the beam splitting ratio of the waveguide splitter can be precisely regulated by the positions and widths of the sub-waveguides.展开更多
Multi-photon lithography has emerged as a powerful tool for photonic integration,allowing to complement planar photonic circuits by 3D-printed freeform structures such as waveguides or micro-optical elements.These str...Multi-photon lithography has emerged as a powerful tool for photonic integration,allowing to complement planar photonic circuits by 3D-printed freeform structures such as waveguides or micro-optical elements.These structures can be fabricated with a high precision on the facets of optical devices and enable highly efficient package-level chip-chip connections in photonic assemblies.However,plain light transport and efficient coupling is far from exploiting the full geometrical design freedom offered by 3D laser lithography.Here,we extended the functionality of 3D-printed optical structures to manipulation of optical polarisation states.We demonstrate compact ultra-broadband polarisation beam splitters(PBSs)that can be combined with polarisation rotators and mode-field adapters into a monolithic 3D-printed structure,fabricated directly on the facets of optical devices.In a proof-of-concept experiment,we demonstrate measured polarisation extinction ratios beyond 11 dB over a bandwidth of 350 nm at near-infrared telecommunication wavelengths around 1550 nm.We demonstrate the viability of the device by receiving a 640 Gbit/s dual-polarisation data signal using 16-state quadrature amplitude modulation(16QAM),without any measurable optical-signal-to-noise-ratio penalty compared to a commercial PBS.展开更多
A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effe...A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effect.At room temperature,a stable dual-wavelength laser and a multi-output port laser which can simultaneously emit single-wavelength lasing and dual-wavelength lasing are obtained.The signal-to-noise ratios(SNRs)for single-wavelength outputs were 54.70 dB and 57.10 dB,with power fluctuations less than 0.038 mW and 0.029 mW,respectively.For dual-wavelength lasing,the SNRs were 59.63 dB and 59.25 dB,with power fluctuations less than 0.018 mW and 0.008 mW,respectively.The center wavelength drift was less than 0.006 nm for both single-wavelength and dual-wavelength outputs.展开更多
In this paper, the reactive splitter network and meta-surface are proposed to radiate the wide-beam isolated element pattern and suppress mutual coupling (MC) of the low-profile phased array with the triangular lattic...In this paper, the reactive splitter network and meta-surface are proposed to radiate the wide-beam isolated element pattern and suppress mutual coupling (MC) of the low-profile phased array with the triangular lattice, respectively. Thus, broadband wide-angle impedance matching (WAIM) is imple-mented to promote two-dimensional (2D) wide scanning. For the isolated element, to radiate the wide-beam patterns approximat-ing to the cosine form, two identical slots backed on one sub-strate integrated cavity are excited by the feeding network con-sisting of a reactive splitter and two striplines connected with splitter output paths. For adjacent elements staggered with each other, with the metasurface superstrate, the even-mode cou-pling voltages on the reactive splitter are cancelled out, yielding reduced MC. With the suppression of MC and the compensa-tion of isolated element patterns, WAIM is realized to achieve 2D wide-angle beam steering up to ± 65° in E-plane, ± 45° in H-plane and ± 60° in D-plane from 4.9 GHz to 5.85 GHz.展开更多
基金supported by grants from the Natural Science Foundation of China(Nos.61275167,60878036and 60178023)the Basic Research Project of Shenzhen(Nos.JCYJ20130329103020637,JCYJ20120613112628842,JCYJ20140418095735591 and JC201005280533A)
文摘In this paper, a novel method of a subwavelength binary simple periodic rectangular structure is presented to realize even beam splitting by combining the rigorous couple-wave analysis with the genetic algorithm. Several even splitters in the terahertz region were designed and one of the silicon-based beam splitters designed to separate one incident beam into four emergent beams has total efficiency up to 92.23 %. Zero-order diffraction efficiency was reduced to less than 0.192 % and the error of uniformity decreased to 6.51 9 10-6. These results break the limitation of even beam splitting based on the traditional scalar theory. In addition, the effects of the incident angle, wavelength, as well as the polarizing angle on the diffraction efficiency and uniformity were also investigated.
基金the Natural Science Foundation from Hubei Province of China[Grant No.2019CFC866]the Guiding Project of Scientific Research Plan of Hubei Education Department of China[Grant No.B2020227]+2 种基金the Collaborative Innovation Team of Discipline Characteristics of Jianghan University[Grant No.03100061]the Research Start-up Funds of Jianghan University[Grant No.101906320001]and the Research Start-up Funds of Jianghan University[101906270002].
文摘In turbomachinery,strong secondary flow can produce significant losses of total pressure near the endwall and reduce the efficiency of the considered turbomachine.In this study,splitters located at different positions with respect to the main blade have been used to reduce such losses and improve the efficiency of the outlet guide vane(OGV).Three different relative positions have been considered assuming a NACA 65-010 profile for both the main blade and the splitter.The numerical results indicate that splitters can effectively reduce the total pressure loss by suppressing the secondary flow around the main blade,but the splitters themselves also produce flow losses,which are caused by flow separation effects.
文摘We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent states.This model induces the production of an attenuated quantum channels based on entangled optical states.Indeed,the decoherence effect is exploited positively here to generate such kind of quantum channels.Next,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.
文摘In this paper, we construct photon-added f-deformed coherent states （PAf-DCSs） for nonlinear bosonic fields by discussing Klauder＇s minimal set of conditions required to obtain coherent states. Using this set of nonlinear states, we propose a very useful scheme for generating the maximal amount of entanglement via unitary beam splitters for different strength regimes of the input field α, deformation q and excitation number m. Therefore, the possibility to create highly entangled states and to control the entanglement is proposed. Moreover, the condition for a maximal and separable output beam state is obtained. Finally, we examine the statistical properties of the PAf-DCSs through the Mandel parameter and exploit a connection between this quantity and the behavior variation of the output state entanglement. Our result may open new perspectives in different tasks of quantum information processing.
文摘An initial structure design of MMI 1×8 optical power splitters is reported.The waveguide material is Si-based SiO2 Ge-doped and deposited by PECVD method.Embedded strip structure is implied in the section design.By using BPM-CAD,a favorable result is obtained that this device has a sound uniformity and fairly low loss.Meanwhile,simulations of designs with certain changed parameters is also implemented for a better design configuration.
文摘The production of maxima and minima by the superposition of two or more light signals provides fundamental support for the wave nature of light. This result is based on the study of wave interference phenomena which remains the only approach to explain the production of those maxima and minima. In a system that is prepared to work with only one photon at a time, any detector can signal only one or zero. In 1986, a rigorously controlled experiment was designed by Grangier, G. Roger, and A. Aspect, [Europhys Lett. 1(4), p. 173, 1986] that guaranteed a single-photon beam. The explanation of the experimental results implied the interference of the wave function of a single-photon with itself. Thus, the explanation of interference that is accepted for an ensemble of photons was assumed to be valid for a single photon. In this study, we prepare a Mach-Zehnder interferometer using the same type of beam splitters used by Grangier et al. to test the assumption mentioned above. Our results allow us to explain the results of Grangier et al. because of the interaction between light and the beam splitters. Our results also verify that their wave interpretation of the results is not valid. Here, we present the essential findings of the extensive experimental evidence that supports our ideas.
基金supported by the National Natural Science Foundation of China(No.62161025)the High-level Talent Introduction Research Program of Shanghai University of Engineering Science(No.2023RC-GC09)the High-Level Local University Construction Innovative Talents Training Program of Shanghai University of Engineering Science(No.25XAI008)。
文摘In optical computing systems for image tasks,optical signals of image data are usually generated by signal modulators,whose speed limits computational performance.To address this,a framework of image memory that can permanently store the image and instantaneously generate its corresponding optical signals has been proposed.In this framework,an original image is sliced into non-overlapping sub-images,each of which contains 3 pixel×3 pixel or 5 pixel×5 pixel,and these subimages are respectively stored in storage units,which are nine-channel or 25-channel power splitters(PSs).The gray values of pixels in each sub-image are sequentially mapped to the light intensity of channels in each PS.These PSs are inversely designed by combining the adjoint method(AM)and the finite-difference frequency-domain method.Using this method,high-performance memory has been realized based on PSs,with a maximum 33.37 dB signal-to-noise ratio.Using multiobjective AM,the storage capacity has been doubled according to the working wavelengths.For example,two sub-images with pixels arranged as‘T'and‘L'shapes can be retrieved at 1310 and 1550 nm,respectively.This framework provides highly stable,non-volatile image storage,and instantaneous generation of optical signals for future all-optical computing systems.
基金National Natural Science Foundation of China(62231001)Hong Kong Research Grants Council Collaborative Research Fund(C1009-22G)。
文摘The beam splitter is one of the most crucial components in optical and electromagnetic systems,and it is also expected to be applied in terahertz(THz)technology.However,most existing beam splitters operate in only a single working mode,restricting their applications.This paper reports a method for the inverse design of a doublet meta-device consisting of two stacked metasurfaces functioning as a reconfigurable THz beam splitter.It is made of photo-curable high-temperature resin using 3D printing technology.By simply adjusting the relative rotation angles between the two metasurfaces to 0°,90°,180°,and 270°,the meta-device can produce four distinct focal patterns,thus achieving four different working modes.This scheme avoids introducing complicated active components,offering a simple,low-cost design of a signal divider in future 6G THz communication systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52271282,51909189 and 52277227)supported by the Open fund of Key Laboratory of Low-grade Energy Utilization Technologies and Systems,Ministry of Education of China,Chongqing University,(Grant No.LLEUTS-202410)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010846)the Shenzhen Science and Technology Programme(Grant Nos.RCYX20231211090210018,WDZC20231125203917001)the Tsinghua Shenzhen International Graduate School via the Scientific Research Start-Up Funds(Grant No.QD2021023C).
文摘To enhance the efficiency of wind energy harvesters,aerodynamic modifications to bluff bodies prove highly effective.This study introduces two innovative galloping piezoelectric energy harvesters(GPEHs)equipped with two symmetrical splitters on a cuboid bluff body:GPEH with upstream splitters(GPEH-US)and GPEH with downstream splitters(GPEH-DS).Wind tunnel experiments evaluated the impact of splitter angle and length on energy harvesting performance across varying wind speeds.The results indicate that larger splitter angles and shorter lengths are more favorable for energy harvesting in GPEH-US.The optimal configuration,determined as GPEH-US with α=90°,L=0.4D,reduces the threshold wind speed,expands the effective wind speed range for energy harvesting,and increases maximum voltage and power output by over 99%,301%,respectively,compared with conventional GPEH.Conversely,GPEH-DS are less effective for energy harvesting but demonstrate potential in vibration control applications.Computational fluid dynamics(CFD)simulations using the OpenFOAM toolbox qualitatively elucidate the physical mechanisms driving these results.A larger splitter angle enables secondary small-scale vortices(SV)to absorb more energy,accelerates boundary layer separation,intensifies and disorderly vortex shedding,enhances aerodynamic instability,and improves energy harvesting performance.
基金supported by the National Key Research&Development Program of China(Grant No.2022YFF0706005)National Natural Science Foundation of China(Grant Nos.12272407,62275269,62275271,and 62305387)+4 种基金Foundation of National University of Defense Technology of China(Grant No.ZK23-03)Hunan Provincial Natural Science Foundation of China(Grant Nos.2022JJ40552 and 2023JJ40683)State Key Laboratory of High Performance Computing,National University of Defense Technology of China(Grant No.202201-12)the Hunan Provincial Innovation Foundation for Postgraduate,China(Grant No.CX20230009)State Key Laboratory of High Performance Computing,National University of Defense Technology of China(Grant No.202201-12).
文摘We study that the different-mode(waveguide-connected)power splitter[(W)PS]can provide different-mode testing points for the optical testing.With the PS or WPS providing two different-mode testing points,the measured insertion losses(ILs)of the three-channel and dual-mode waveguide crossing(WC)for both the fundamental transverse electric(TE0)and TE1 modes are less than 1.8 dB or 1.9 dB from 1540 nm to 1560 nm.At the same time,the crosstalks(CTs)are lower than-17.4 dB or-18.2 dB.The consistent test results indicate the accuracy of the(W)PS-based testing circuit.Additionally,combining the tunable tap couplers,the(W)PS can provide multiple testing points with different modes and different transmittances.
基金supported by the National Natural Science Foundation of China(Nos.61775136 and 11721091)
文摘Separating lights into different, paths according to the polarization states while keeping their respective path's polarizations with high purification is keen for polarization multiplex in optical communications. Metallic nanowire gratings with multi-slits in a period are proposed to achieve polarized beam splitters (PBSs) in reflection and diffraction. The setting of multi-slits largely reduces the reflection of photons with a transverse magnetific field via the plasmonic waveguiding effect, which leads to highly polarized output lights with extinction ratio larger than 20 dB in each channel. The proposed reflection/diffraction PBSs enrich the approaches to control the polarization states with the advantages of wide incident angles and flexible beam splitting angles.
基金supported in part by the National Natural Science Foundation of China (No. 60977050)the National "973" Program of China (Nos. 2009CB320302 and 2011CB301704)
文摘Two types of 1×2 multi-mode interference （MMI） splitters with splitting ratios of 85：15 and 72：28 are designed. On the basis of a numerical simulation, an optimal length of the MMI section is obtained. Subsequently, the devices are fabricated and tested. The footprints of the rectangular MMI regions are only 3×18.2 and 3×14.3 （#m）. The minimum excess losses are 1.4 and 1.1 dB. The results of the test on the splitting ratios are consistent with designed values. The devices can be applied in ultra-compact photonic integrated circuits to realize the ＂tap＂ function.
基金the support of the Innovation Fund for National Natural Science Foundation of China(52009050,52461047)Gansu Provincial Higher Education Innovation Fund(2025A-033).
文摘To simultaneously reduce flow-induced noise and enhance hydraulic performance in centrifugal pumps,this study proposes a bionic volute tongue inspired by the serrated trailing-edge morphology of the long-eared owl wing.Hydraulic performance and volute-induced noise are integrated into a unified evaluation framework,enabling multi-objective optimization of the tongue geometry.An orthogonal experimental design coupled with Computational Fluid Dynamics(CFD)and Computational Fluid Acoustics(CFA)is employed to systematically assess the influence of serration parameters.A matrix-based decision method is then used to identify the optimal configuration balancing efficiency,head,and acoustic performance.The optimized design reduces the area fraction of extremely high-velocity regions(>18 m/s)from 15.21% to 5.38%,corresponding to a 64.63% decrease,while the flow non-uniformity coefficientζis reduced by 26.1%.Under rated operating conditions,the pump head increases by 0.5 m,hydraulic efficiency improves by 5%,and volute-induced noise is reduced by approximately 5 dB.Flow-field analysis indicates that volute-induced noise is the dominant source of hydrodynamic noise,and that the serrated bionic tongue effectively suppresses its intensity.The noise reduction mechanism is attributed to improved rotor-stator interaction,decomposition of large-scale vortical structures,and delayed flow separation,which collectively reduce pressure pulsation at the rotor-stator interface.
基金the School of Engineering and Built Environment at Anglia Ruskin University,UK,for the supportthe support of IRC-CSS and the Electrical Engineering Department,KFUPM,Saudi Arabia。
文摘We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semiconductor lasers,as well as Raman and semiconductor optical amplifiers.Although inverse design approaches for optical detectors remain relatively underexplored,we examine optical layers,particularly metamaterial absorbers,as promising candidates for high-performance optical detection.In addition,we underscore advancements in inverse designing passive optical components,including beam splitters,gratings,and optical fibers.These optical blocks are fundamental in developing next-generation standalone optical communication systems and optical sensing networks,including integrated sensing and communication technologies.While categorizing various reported deep learning architectures across five paradigms,we offer a paradigm-based perspective that reveals how different ML techniques function within modern inverse design methods and enable fast,data-driven solutions that significantly reduce design time and computational demands compared with traditional optimization methods.
基金supported by the Korea Institute of Industrial Technology Evaluation and Planning (ITEP) grant funded by the Ministry of Knowledge Economy (No.10032063)
文摘This paper describes the optimization of the impeller having splitters for a turbo blower.Two design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower performance.Blower pressure and ef-ficiency are selected as an object function,and the optimization of the blower impeller is performed by a response surface method (RSM).Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each case.Throughout the shape optimization of the splitters attached to the impeller in the turbo blower,pressure and efficiency at the design flow condition are suc-cessively increased by 5.9 percent and 17.9 percent respectively based on the reference blower.The higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of im-peller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference blower.For the object function of pressure,pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference blower.The enhancement of blow-er performance is due to the reduction of reverse and circulation flows in the blade passage.
文摘The soft X-ray interferometry is completed by the Mach-Zehnder interferometer using a soft X-ray laser, and it is also an important method to measure the electron densities of a laser-produced plasma near the critical surface. It is apparently demonstrated in this paper that the incident angle of each optical element in the soft X-ray Mach- Zehnder interferometer should be near normal incidence based on the polarized characteristics of the soft X-ray mul-tilayers, and the product of reflectivity and transmission of the beam splitter should be taken as a standard of design according to the structure of the soft X-ray Mach-Zehnder interferometer. The beam splitters used in the soft X-ray interferometry at 13.9 nm are fabricated using the ion beam sputtering. The figure error of the beam splitter has reached the nanometer magnitude, in which the product of reflectiv-ity and transmission of the beam splitter is more than 1.6%.
基金supported by the National Natural Science Foundation of China(No.12274236)the Open Foundation of State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202320).
文摘In this Letter,waveguide beam splitters(1×3)with type I modifications are fabricated in a LiNbO_(3) crystal by femtosecond laser direct writing.The influence of the relative positions of three sub-waveguides on power splitting ratios are investigated in detail and the corresponding output intensities as functions of the relative positions in the numerical simulation are plotted,which are in good accordance with the experimental results.In addition,the waveguide beam splitter with a 1:1:1 splitting ratio is fabricated by changing the relative widths of the three branch-waveguides.Guiding performances at 532 nm are measured and analyzed by a typical end-face coupling system.The simulation and experimental results demonstrate that the beam splitting ratio of the waveguide splitter can be precisely regulated by the positions and widths of the sub-waveguides.
基金supported by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)in the framework of the Collaborative Research Center(CRC)Wave Phenomena(SFB 1173,project-ID 258734477)under Germany's Excellence Strategy via the Excellence Cluster 3D Matter Made to Order(EXC-2082/1–390761711)+4 种基金by the Bundesministerium für Bildung und Forschung(BMBF)within the projects PRIMA(#13N14630),DiFeMiS(#16ES0948),Open6GHub(#16KISK010)by the European Research Council(ERC Consolidator Grant‘TeraSHAPE’,#773248)by the Photonic Packaging Pilot Line PIXAPP(#731954)by the Alfried Krupp von Bohlen und Halbach Foundation,by the Karlsruhe School of Optics and Photonics(KSOP)by the Karlsruhe Nano-Micro Facility(KNMF).A.N.was supported by the Erasmus Mundus Joint Doctorate Programme Europhotonics(grant number 159224-1-2009-1-FR-ERA MUNDUS-EMJD).
文摘Multi-photon lithography has emerged as a powerful tool for photonic integration,allowing to complement planar photonic circuits by 3D-printed freeform structures such as waveguides or micro-optical elements.These structures can be fabricated with a high precision on the facets of optical devices and enable highly efficient package-level chip-chip connections in photonic assemblies.However,plain light transport and efficient coupling is far from exploiting the full geometrical design freedom offered by 3D laser lithography.Here,we extended the functionality of 3D-printed optical structures to manipulation of optical polarisation states.We demonstrate compact ultra-broadband polarisation beam splitters(PBSs)that can be combined with polarisation rotators and mode-field adapters into a monolithic 3D-printed structure,fabricated directly on the facets of optical devices.In a proof-of-concept experiment,we demonstrate measured polarisation extinction ratios beyond 11 dB over a bandwidth of 350 nm at near-infrared telecommunication wavelengths around 1550 nm.We demonstrate the viability of the device by receiving a 640 Gbit/s dual-polarisation data signal using 16-state quadrature amplitude modulation(16QAM),without any measurable optical-signal-to-noise-ratio penalty compared to a commercial PBS.
基金supported by the Key Scientific Research Project of Hunan Education Department,China(No.23A0446)the Natural Science Foundation of Hunan Province,China(provinces and cities combined)(No.2022JJ50067)+1 种基金the Hunan Province Degree and Postgraduate Teaching Reform Research Project,China(No.2022JGYB182)the Scientific Research and Innovation Foundation of Hunan University of Technology(No.CX2314).
文摘A dual-wavelength ring-cavity erbium-doped fiber(EDF)laser is designed based on two polarization beam splitters(PBSs)and a polarization controller(PC)performing gain equalization and polarization hole burning(PHB)effect.At room temperature,a stable dual-wavelength laser and a multi-output port laser which can simultaneously emit single-wavelength lasing and dual-wavelength lasing are obtained.The signal-to-noise ratios(SNRs)for single-wavelength outputs were 54.70 dB and 57.10 dB,with power fluctuations less than 0.038 mW and 0.029 mW,respectively.For dual-wavelength lasing,the SNRs were 59.63 dB and 59.25 dB,with power fluctuations less than 0.018 mW and 0.008 mW,respectively.The center wavelength drift was less than 0.006 nm for both single-wavelength and dual-wavelength outputs.
基金supported by Sichuan Science and Technology Programs(2022NSFSC0547,2022ZYD0109)the 2020 Open Foundation of Key Laboratory of Cognitive Radio and Information Processing,Ministry of Education(Guilin University of Electronic Technology)(CRKL200201).
文摘In this paper, the reactive splitter network and meta-surface are proposed to radiate the wide-beam isolated element pattern and suppress mutual coupling (MC) of the low-profile phased array with the triangular lattice, respectively. Thus, broadband wide-angle impedance matching (WAIM) is imple-mented to promote two-dimensional (2D) wide scanning. For the isolated element, to radiate the wide-beam patterns approximat-ing to the cosine form, two identical slots backed on one sub-strate integrated cavity are excited by the feeding network con-sisting of a reactive splitter and two striplines connected with splitter output paths. For adjacent elements staggered with each other, with the metasurface superstrate, the even-mode cou-pling voltages on the reactive splitter are cancelled out, yielding reduced MC. With the suppression of MC and the compensa-tion of isolated element patterns, WAIM is realized to achieve 2D wide-angle beam steering up to ± 65° in E-plane, ± 45° in H-plane and ± 60° in D-plane from 4.9 GHz to 5.85 GHz.
