In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide a...In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna,coupled to photonic crystal waveguide through photonic crystal cavity,and radiated outward through slots at the top layer of antenna.The simulation results show that the antenna achieves a peak gain of 13.45 dBi at 360 GHz,a half-power beam width of 10.9°,and a side lobe level of−13.9 dB.The antenna based on photonic crystal has the advantages of low profile,low loss,and high radiation efficiency,which can be applied to terahertz wireless communication systems.展开更多
A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The...A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The stress distribution and effective refractive index of waveguide fabricated by this approach are calculated using finite element and finite difference beam propagation method,respectively.The results of these studies indicate that the stress of silica on silicon optical waveguide can be matched in parallel and vertical direction and AWG polarization dependent wavelength (PDλ) can be reduced effectively due to side-silicon layer.展开更多
This paper reports on the design, fabrication,and performance of a high-reflectivity large-rotation mirror array for MEMS （micro-electro-mechanical system） 16 × 16 optical switches. The mirror in the array can ...This paper reports on the design, fabrication,and performance of a high-reflectivity large-rotation mirror array for MEMS （micro-electro-mechanical system） 16 × 16 optical switches. The mirror in the array can enlarge its rotation an- gles up to 90° and keep a steady state to steer the optical signal. According to the large-rotation behavior, an electro- mechanical model of the mirror is presented. By monolithic integration of fiber grooves and mirrors fabricated by a sur- face and bulk hybrid micromachining process, the coarse passive alignment of fiber-mirror-fiber can be achieved. The re- flectivity of the mirror is measured to be 93.1% ~96.3%. The switches demonstrate that the smallest fiber-mirror-fiber insertion loss is 2. ldB using OptiFocusTM collimating lensed fibers. Moreover,only about ＋- 0.01dB oscillating amplitude of insertion loss is provoked after the device is tested for 15min for 5-90Hz in the vertical vibration amplitude of 3mm.展开更多
A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channe...A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channel AWGs with200 GHz spacing and a Mach-Zehnder interferometer(MZI)with 200 GHz free spectral range.The 16 channels of one silicon AWG are interleaved with those of the other AWG in spectrum,but with an identical spacing of 200 GHz.For the composed wavelength division multiplexer,the experiment results reveal 32 wavelength channels in C-band,a wavelength spacing of 100 GHz,and a channel crosstalk lower than-15 dB.展开更多
The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large...The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large number of Ag-filament TS selectors,V_(th)and V_(hold)are extracted and their variations distribution expressions are obtained,which are then employed to evaluate the impact on read process and write process in 32×321 S1 R crossbar array under different bias schemes.The results indicate that V_(th)and V_(hold)variations of TS selector can lead to degradation of 1 S1 R array performance parameters,such as minimum read/write voltage,bit error rate(BER),and power consumption.For the read process,a small V_(hold)variation not only results in the minimum read voltage increasing but it also leads to serious degradation of BER.As the standard deviation of V_(hold)and V_(th)increases,the BER and the power consumption of 1 S1 R crossbar array under 1/2 bias,1/3 bias,and floating scheme degrade,and the case under 1/2 bias tends to be more serious compared with other two schemes.For the write process,the minimum write voltage also increases with the variation of V_(hold)from small to large value.A slight increase of V_(th)standard deviation not only decreases write power efficiency markedly but also increases write power consumption.These results have reference significance to understand the voltage variation impacts and design of selector properly.展开更多
We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelen...We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelength is assumed to be 1550 nm. The simulation results show a ?14.66 dB extinction ratio. Downscaling the silicon waveguide in MIM structure leads to enhancement of the effective Kerr nonlinearity due to tight mode confinement. Also, using O+ ions implanted into silicon, the switching time less than 10 ps and a delay time less than 8 fs are achieved. The overall length of the switch is 550 nm.展开更多
We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometr...We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refrac- tive index. Aseamless joint structure has been designed and fabricated for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array. The highest simulation quantum efficiency could achieve 92% when the matching layer thickfiess of the PD is 120 nm and the insertion length is 2 μm. The fabricated PD with 320-nm-thick match.ing layer and 2-μm-length insertion matching layer present a responsivity of 0.87 A/W.展开更多
A novel approach devoted to achieving ultra-wideband radar cross section reduction（RCSR） of a waveguide slot antenna array（WGSAA） while maintaining its radiation performance is proposed. Three kinds of artificial ...A novel approach devoted to achieving ultra-wideband radar cross section reduction（RCSR） of a waveguide slot antenna array（WGSAA） while maintaining its radiation performance is proposed. Three kinds of artificial magnetic conductors（AMCs） tiles consisting of three types of basic units resonant at different frequencies are designed and arranged in a novel quadruple-triangle-type configuration to create a composite planar metasurface. The proposed metasurface is characterized by low radar feature over an ultra-wideband based on the principle of phase cancellation. Both simulated and measured results demonstrate that after the composite metasurface is used to cover part of the antenna array, an ultrawideband RCSR involving in-band and out-of-band is achieved for co-and cross-polarized incident waves based on energy cancellation, while the radiation performance is well retained. The proposed method is simple, low-cost, and easy-tofabricate, providing a new method for ultra-wideband RCSR of an antenna array. Moreover, the method proposed in this paper can easily be applied to other antenna architectures.展开更多
In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characte...In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characteristics of SOA,it can act as the gain medium as well as light source.The AWG module is used as the wavelength demodulator.It is shown that SOA-based FRL sensors can accurately respond to 1.5μεdynamic strain signal with high frequency up to 120 k Hz and almost no distortion in the waveforms.Experimental results show that the system can be used for acoustic testing,such as underwater ultrasonic detection and external impact monitoring.In addition,the simultaneous dual-channel demodulated system is investigated in detail to verify the multiplexing.This dynamic strain sensing system can be widely utilized in structural health monitoring because of its high stability,low cost and good multiplexability.展开更多
In this work,we demonstrated high-power quantum cascade laser(QCL)arrays lasing at λ~5μm by employing an optimized coupled-ridge waveguide(CRW)structure.Five-element QCL arrays were simulated and fabricated through ...In this work,we demonstrated high-power quantum cascade laser(QCL)arrays lasing at λ~5μm by employing an optimized coupled-ridge waveguide(CRW)structure.Five-element QCL arrays were simulated and fabricated through a two-step etching method to extend the CRW structure to a mid-wave infrared regime.A lateral far-field with the main peak near a diffraction-limited intensity curve of about 10°was observed by properly designing a geometric shape of the ridges and interspaces.By introducing a buried 2nd-order distributed feedback(DFB)grating,substrate emission with a radiation power above 1 W at 25℃ is achieved.Single longitudinal mode operation is obtained by changing the temperature of the heatsink with a good linear wavelength tuning coefficient of -0.2 cm^(-1)/K.展开更多
In conventional High Power Microwave(HPM)waveguide arrays of longitudinal shunt slots,the mutual coupling of slots in different waveguide can badly decrease the capability of wide-angle scanning of array.For this reas...In conventional High Power Microwave(HPM)waveguide arrays of longitudinal shunt slots,the mutual coupling of slots in different waveguide can badly decrease the capability of wide-angle scanning of array.For this reason,an L-band HPM waveguide array of longitudinal shunt slots was designed.The choke groove was adopted to restrain the mutual coupling of slots of the HPM array antenna.The results of simulation are:the scanning angle of array without choke groove structure with the gain of antenna decreased 3 dB is only 24.7°,and it is 33.0°for array with choke groove structure;the wideband of active reflection of array have been improved with choke groove structure,the bandwidth of VSWR≤3 of array with choke groove is 6.6%,and that is 5.0%without choke groove;the power-handling capacity of array antenna with scanning angle of 35°can reach 957 MW,which is a little less than that of array without scanning(1008MW).展开更多
An optical routing-switching technology based on optical switch array is proposed.The characteristics of the blocking and nonblocking networks are analyzed and compared,odd-even sorting network is used to realize opti...An optical routing-switching technology based on optical switch array is proposed.The characteristics of the blocking and nonblocking networks are analyzed and compared,odd-even sorting network is used to realize optical routing-switching,relative routing-switching protocol is designed.Simulation test under load shows that it can reduce a blocking effectively and enhance an efficiency of switching.Further,it can transfer the processing and switching within parallel computer from electric domain to optical domain. It can make parallel computer coordinating computing and processing at much more higher speed, storing and transmitting even more efficiently.展开更多
The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring ar...The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring arrayed waveguide distance ΔL, the channel frequency interval Δf, and the free spectral range. The structure of 4×4 AWG is designed and the result of stimulated test is also given. Analysis shows that the 4×4 AWG is characterized by a wide dynamic range, low crosstalk, better spectrum properties, and a compact structure.展开更多
Monopulse slot antenna arrays based on substrate integrated waveguide （SIW） are proposed for the application of 60 GHz mono- pulse tracking systems in this paper. The sum-difference monopulse comparator can provide ...Monopulse slot antenna arrays based on substrate integrated waveguide （SIW） are proposed for the application of 60 GHz mono- pulse tracking systems in this paper. The sum-difference monopulse comparator can provide a high amplitude and phase balance over wide frequency band and no phase delay technique is required for the difference channel. Resonant slot antennas are adopted as the radiating elements since they can be integrated with the sum-difference monopulse comparator in a single layer with a compact size. Two monopulse arrays with 2× 4 and 4×4 slot elements are designed, fabricated, and measured. Measured results show that the proposed antenna arrays have wide bandwidth covering the unlicensed 60-GHz band. The peak sum beam gain is 13.85 dBi for the 2 ×4 element array and 16.24 dBi for the 4×4 element array. The peak difference beam gain is 11.20 dBi for the 2×4 element array and 12.11 dBi for the 4×4 element array and the maximum null depth can reach -40 dB.展开更多
In this paper,a new type of optically controllable silicon slab loaded E-plane millimeterwave rectangular waveguide switch is presented.It uses SELFOC lens to couple optical puls-es to silicon slab with optical fiber....In this paper,a new type of optically controllable silicon slab loaded E-plane millimeterwave rectangular waveguide switch is presented.It uses SELFOC lens to couple optical puls-es to silicon slab with optical fiber.The on/off ratio reaches 42dB,the front fringe of suchkind swith is less than 0.05μs,and the insertion loss is less than 1dB in the full band of 26.5GHz to 40GHz.展开更多
The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication proce...The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication process on the AWG is achieved by the design of bi-level tapers. The wavelength tuning of the AWG is achieved according to the thermo-optic effect of silicon, and uniform heating of the silicon waveguide layer is achieved by optimizing the heater design. The fabricated AWG shows a minimum crosstalk of 16 dB, a maximum insertion loss of 3.91 dB and a wavelength tuning efficiency of 8.92 nm/W, exhibiting a ～8 dB improvement of crosstalk, ～2.1 dB improvement of insertion loss and ～5 nm/W improvement of wavelength tuning efficiency, compared to our previous reported results.展开更多
A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum ...A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum response. However, the central wavelength and channel spacing are deviated from the design values. To improve their accuracy, an optimized design is adopted to compensate the process error. As a result, the central wavelength 1549.9 nm and channel spacing 1.59 nm are obtained in the experiment, while their design values are 1549.32 nm and 1.6 nm, respectively. The route capability and thermo-optic characteristic of the AWG are also discussed in detail.展开更多
In this paper, experimental and theoretical studies of the output mode characteristics of an in-phase locked gain waveguide array CO2 laser are reported. The experimental results of the optical oscillation mode freque...In this paper, experimental and theoretical studies of the output mode characteristics of an in-phase locked gain waveguide array CO2 laser are reported. The experimental results of the optical oscillation mode frequency, the far-field intensity distribution and the burnt pattern of the sliced waveguide array laser are obtained. A revised mode expression of the rectangle waveguide, which is suited for this waveguide array CO2 laser, is proposed. The theoretical simulation results based on the revised mode expression are shown to be in good agreement with the experimental results.展开更多
Memory access fast switching structures in cluster are studied,and three kinds of fast switching structures（ FS,LR2 SS,and LAPS） are proposed. A mixed simulation test bench is constructed and used for statistic of d...Memory access fast switching structures in cluster are studied,and three kinds of fast switching structures（ FS,LR2 SS,and LAPS） are proposed. A mixed simulation test bench is constructed and used for statistic of data access delay among these three structures in various cases. Finally these structures are realized on Xilinx FPGA development board and DCT,FFT,SAD,IME,FME,and de-blocking filtering algorithms are mapped onto the structures. Compared with available architectures,our proposed structures have lower data access delay and lower area.展开更多
Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-...Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies.For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.展开更多
基金supported by the National Natural Science Foundation of China(No.62375031)the Basic Research Project of Chongqing Science and Technology Commission(No.CSTC-2021jcyj-bsh0194)the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJQN202200602)。
文摘In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna,coupled to photonic crystal waveguide through photonic crystal cavity,and radiated outward through slots at the top layer of antenna.The simulation results show that the antenna achieves a peak gain of 13.45 dBi at 360 GHz,a half-power beam width of 10.9°,and a side lobe level of−13.9 dB.The antenna based on photonic crystal has the advantages of low profile,low loss,and high radiation efficiency,which can be applied to terahertz wireless communication systems.
文摘A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The stress distribution and effective refractive index of waveguide fabricated by this approach are calculated using finite element and finite difference beam propagation method,respectively.The results of these studies indicate that the stress of silica on silicon optical waveguide can be matched in parallel and vertical direction and AWG polarization dependent wavelength (PDλ) can be reduced effectively due to side-silicon layer.
文摘This paper reports on the design, fabrication,and performance of a high-reflectivity large-rotation mirror array for MEMS （micro-electro-mechanical system） 16 × 16 optical switches. The mirror in the array can enlarge its rotation an- gles up to 90° and keep a steady state to steer the optical signal. According to the large-rotation behavior, an electro- mechanical model of the mirror is presented. By monolithic integration of fiber grooves and mirrors fabricated by a sur- face and bulk hybrid micromachining process, the coarse passive alignment of fiber-mirror-fiber can be achieved. The re- flectivity of the mirror is measured to be 93.1% ~96.3%. The switches demonstrate that the smallest fiber-mirror-fiber insertion loss is 2. ldB using OptiFocusTM collimating lensed fibers. Moreover,only about ＋- 0.01dB oscillating amplitude of insertion loss is provoked after the device is tested for 15min for 5-90Hz in the vertical vibration amplitude of 3mm.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFB2203600)。
文摘A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channel AWGs with200 GHz spacing and a Mach-Zehnder interferometer(MZI)with 200 GHz free spectral range.The 16 channels of one silicon AWG are interleaved with those of the other AWG in spectrum,but with an identical spacing of 200 GHz.For the composed wavelength division multiplexer,the experiment results reveal 32 wavelength channels in C-band,a wavelength spacing of 100 GHz,and a channel crosstalk lower than-15 dB.
基金Project supported by the MOST of China(Grant No.2016YFA0201801)the Beijing Advanced Innovation Center for Future Chip(ICFC)+2 种基金Beijing Municipal Science and Technology Project(Grant No.D161100001716002)the National Natural Science Foundation of China(Grant Nos.61674089,61674087,61674092,61076115,and 61774012)the Research Fund from Beijing Innovation Center for Future Chip(Grant No.KYJJ2016008)
文摘The impact of the variations of threshold voltage(V_(th))and hold voltage(V_(hold))of threshold switching(TS)selector in1 S1 R crossbar array is investigated.Based on ON/OFF state I–V curves measurements from a large number of Ag-filament TS selectors,V_(th)and V_(hold)are extracted and their variations distribution expressions are obtained,which are then employed to evaluate the impact on read process and write process in 32×321 S1 R crossbar array under different bias schemes.The results indicate that V_(th)and V_(hold)variations of TS selector can lead to degradation of 1 S1 R array performance parameters,such as minimum read/write voltage,bit error rate(BER),and power consumption.For the read process,a small V_(hold)variation not only results in the minimum read voltage increasing but it also leads to serious degradation of BER.As the standard deviation of V_(hold)and V_(th)increases,the BER and the power consumption of 1 S1 R crossbar array under 1/2 bias,1/3 bias,and floating scheme degrade,and the case under 1/2 bias tends to be more serious compared with other two schemes.For the write process,the minimum write voltage also increases with the variation of V_(hold)from small to large value.A slight increase of V_(th)standard deviation not only decreases write power efficiency markedly but also increases write power consumption.These results have reference significance to understand the voltage variation impacts and design of selector properly.
文摘We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelength is assumed to be 1550 nm. The simulation results show a ?14.66 dB extinction ratio. Downscaling the silicon waveguide in MIM structure leads to enhancement of the effective Kerr nonlinearity due to tight mode confinement. Also, using O+ ions implanted into silicon, the switching time less than 10 ps and a delay time less than 8 fs are achieved. The overall length of the switch is 550 nm.
基金Project supported by the National High Technology Research and Development Program of China(Grant Nos.2013AA031401,2015AA016902,and 2015AA016904)the National Natural Science Foundation of China(Grant Nos.61176053,61274069,and 61435002)the National Basic Research Program of China(Grant Nos.2012CB933503 and 2013CB932904)
文摘We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refrac- tive index. Aseamless joint structure has been designed and fabricated for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array. The highest simulation quantum efficiency could achieve 92% when the matching layer thickfiess of the PD is 120 nm and the insertion length is 2 μm. The fabricated PD with 320-nm-thick match.ing layer and 2-μm-length insertion matching layer present a responsivity of 0.87 A/W.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61671464,61701523,and 61471389)
文摘A novel approach devoted to achieving ultra-wideband radar cross section reduction（RCSR） of a waveguide slot antenna array（WGSAA） while maintaining its radiation performance is proposed. Three kinds of artificial magnetic conductors（AMCs） tiles consisting of three types of basic units resonant at different frequencies are designed and arranged in a novel quadruple-triangle-type configuration to create a composite planar metasurface. The proposed metasurface is characterized by low radar feature over an ultra-wideband based on the principle of phase cancellation. Both simulated and measured results demonstrate that after the composite metasurface is used to cover part of the antenna array, an ultrawideband RCSR involving in-band and out-of-band is achieved for co-and cross-polarized incident waves based on energy cancellation, while the radiation performance is well retained. The proposed method is simple, low-cost, and easy-tofabricate, providing a new method for ultra-wideband RCSR of an antenna array. Moreover, the method proposed in this paper can easily be applied to other antenna architectures.
基金supported by the National Natural Science Foundation of China(No.51874064)the Project of Graduate Innovation in Chongqing University of Technology(No.gzlcx20223295)。
文摘In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characteristics of SOA,it can act as the gain medium as well as light source.The AWG module is used as the wavelength demodulator.It is shown that SOA-based FRL sensors can accurately respond to 1.5μεdynamic strain signal with high frequency up to 120 k Hz and almost no distortion in the waveforms.Experimental results show that the system can be used for acoustic testing,such as underwater ultrasonic detection and external impact monitoring.In addition,the simultaneous dual-channel demodulated system is investigated in detail to verify the multiplexing.This dynamic strain sensing system can be widely utilized in structural health monitoring because of its high stability,low cost and good multiplexability.
基金supported by National Basic Research Program of China(Grant Nos.2018YFA0209103,2018YFB2200504)in part by National Natural Science Foundation of China(Grant Nos.61991430,61774146,61790583,61734006,61835011,61674144,61774150,61805168)+1 种基金in part by Beijing Municipal Science&Technology Commission(Grant No.Z201100004020006)in part by the Key projects of the Chinese Academy of Sciences(Grant No.2018147,Grant No.YJKYYQ20190002,Grant No.QYZDJ-SSW-JSC027,Grant No.XDB43000000,Grant No.ZDKYYQ20200006).
文摘In this work,we demonstrated high-power quantum cascade laser(QCL)arrays lasing at λ~5μm by employing an optimized coupled-ridge waveguide(CRW)structure.Five-element QCL arrays were simulated and fabricated through a two-step etching method to extend the CRW structure to a mid-wave infrared regime.A lateral far-field with the main peak near a diffraction-limited intensity curve of about 10°was observed by properly designing a geometric shape of the ridges and interspaces.By introducing a buried 2nd-order distributed feedback(DFB)grating,substrate emission with a radiation power above 1 W at 25℃ is achieved.Single longitudinal mode operation is obtained by changing the temperature of the heatsink with a good linear wavelength tuning coefficient of -0.2 cm^(-1)/K.
文摘In conventional High Power Microwave(HPM)waveguide arrays of longitudinal shunt slots,the mutual coupling of slots in different waveguide can badly decrease the capability of wide-angle scanning of array.For this reason,an L-band HPM waveguide array of longitudinal shunt slots was designed.The choke groove was adopted to restrain the mutual coupling of slots of the HPM array antenna.The results of simulation are:the scanning angle of array without choke groove structure with the gain of antenna decreased 3 dB is only 24.7°,and it is 33.0°for array with choke groove structure;the wideband of active reflection of array have been improved with choke groove structure,the bandwidth of VSWR≤3 of array with choke groove is 6.6%,and that is 5.0%without choke groove;the power-handling capacity of array antenna with scanning angle of 35°can reach 957 MW,which is a little less than that of array without scanning(1008MW).
文摘An optical routing-switching technology based on optical switch array is proposed.The characteristics of the blocking and nonblocking networks are analyzed and compared,odd-even sorting network is used to realize optical routing-switching,relative routing-switching protocol is designed.Simulation test under load shows that it can reduce a blocking effectively and enhance an efficiency of switching.Further,it can transfer the processing and switching within parallel computer from electric domain to optical domain. It can make parallel computer coordinating computing and processing at much more higher speed, storing and transmitting even more efficiently.
文摘The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring arrayed waveguide distance ΔL, the channel frequency interval Δf, and the free spectral range. The structure of 4×4 AWG is designed and the result of stimulated test is also given. Analysis shows that the 4×4 AWG is characterized by a wide dynamic range, low crosstalk, better spectrum properties, and a compact structure.
基金This project is supported by the National Basic Research Program of China （＂973＂ Program） under Grant No. 2014CB339900 and the National Natural Science Foundation of China under Grant No. 61372056.
文摘Monopulse slot antenna arrays based on substrate integrated waveguide （SIW） are proposed for the application of 60 GHz mono- pulse tracking systems in this paper. The sum-difference monopulse comparator can provide a high amplitude and phase balance over wide frequency band and no phase delay technique is required for the difference channel. Resonant slot antennas are adopted as the radiating elements since they can be integrated with the sum-difference monopulse comparator in a single layer with a compact size. Two monopulse arrays with 2× 4 and 4×4 slot elements are designed, fabricated, and measured. Measured results show that the proposed antenna arrays have wide bandwidth covering the unlicensed 60-GHz band. The peak sum beam gain is 13.85 dBi for the 2 ×4 element array and 16.24 dBi for the 4×4 element array. The peak difference beam gain is 11.20 dBi for the 2×4 element array and 12.11 dBi for the 4×4 element array and the maximum null depth can reach -40 dB.
文摘In this paper,a new type of optically controllable silicon slab loaded E-plane millimeterwave rectangular waveguide switch is presented.It uses SELFOC lens to couple optical puls-es to silicon slab with optical fiber.The on/off ratio reaches 42dB,the front fringe of suchkind swith is less than 0.05μs,and the insertion loss is less than 1dB in the full band of 26.5GHz to 40GHz.
基金Supported by the National Key R&D Program of China under Grant No 2016YFB0402504
文摘The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication process on the AWG is achieved by the design of bi-level tapers. The wavelength tuning of the AWG is achieved according to the thermo-optic effect of silicon, and uniform heating of the silicon waveguide layer is achieved by optimizing the heater design. The fabricated AWG shows a minimum crosstalk of 16 dB, a maximum insertion loss of 3.91 dB and a wavelength tuning efficiency of 8.92 nm/W, exhibiting a ～8 dB improvement of crosstalk, ～2.1 dB improvement of insertion loss and ～5 nm/W improvement of wavelength tuning efficiency, compared to our previous reported results.
基金Project supported by the National High Technology Research and Development Program of China(Grant Nos.2011AA010303 and 2013AA031401)the National Natural Science Foundation of China(Grant No.61090390)
文摘A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum response. However, the central wavelength and channel spacing are deviated from the design values. To improve their accuracy, an optimized design is adopted to compensate the process error. As a result, the central wavelength 1549.9 nm and channel spacing 1.59 nm are obtained in the experiment, while their design values are 1549.32 nm and 1.6 nm, respectively. The route capability and thermo-optic characteristic of the AWG are also discussed in detail.
文摘In this paper, experimental and theoretical studies of the output mode characteristics of an in-phase locked gain waveguide array CO2 laser are reported. The experimental results of the optical oscillation mode frequency, the far-field intensity distribution and the burnt pattern of the sliced waveguide array laser are obtained. A revised mode expression of the rectangle waveguide, which is suited for this waveguide array CO2 laser, is proposed. The theoretical simulation results based on the revised mode expression are shown to be in good agreement with the experimental results.
基金Supported by the National Natural Science Foundation of China(61272120,61634004,61602377)the Shaanxi Provincial Co-ordination Innovation Project of Science and Technology(2016KTZDGY02-04-02)Scientific Research Program Funded by Shannxi Provincial Education Department(17JK0689)
文摘Memory access fast switching structures in cluster are studied,and three kinds of fast switching structures（ FS,LR2 SS,and LAPS） are proposed. A mixed simulation test bench is constructed and used for statistic of data access delay among these three structures in various cases. Finally these structures are realized on Xilinx FPGA development board and DCT,FFT,SAD,IME,FME,and de-blocking filtering algorithms are mapped onto the structures. Compared with available architectures,our proposed structures have lower data access delay and lower area.
基金supported by the National Natural Science Foundation of China (Grant No. 12105025)。
文摘Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies.For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.
