According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operati...According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operating mechanism is analyzed. The thermal resistor acts as the excited unit, and the piezoresistive unit acts as the detector, for the above micro sensor. By using the amplitude and phase conditions, the self exciting closed loop system is investigated based on the operating mechanism for the abov...展开更多
The purpose of the present work is to quantify the influences of the discrete nature, the surface effects, and the large deformation on the bending resonant properties of long and ultrathin （100） silicon nanocantile...The purpose of the present work is to quantify the influences of the discrete nature, the surface effects, and the large deformation on the bending resonant properties of long and ultrathin （100） silicon nanocantilevers. We accomplish this by using an analytical semi-continuum Keating model within the framework of nonlinear, finite deformation kinematics. The semi-continuum model shows that the elastic behaviors of the silicon nanocantilevers are size-dependent and surface- dependent, which agrees well with the molecular dynamics results. It also indicates that the dominant effect on the fundamental resonant frequency shift of the silicon nanocantilever is adsorption-induced surface stress, followed by the discrete nature and surface reconstruction, whereas surface relaxation has the least effect. In particular, it is found that a large deformation tends to increase the nonlinear fundamental frequency of the silicon nanocantilever, depending not only on its size but also on the surface effects. Finally, the resonant frequency shifts due to the adsorption-induced surface stress predicted by the current model are quantitatively compared with those obtained from the experimental measurement and the other existing approach. It is noticed that the length-to-thickness ratio is the key parameter that correlates the deviations in the resonant frequencies predicted from the current model and the empirical formula.展开更多
Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency...Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency drift as we adjusted the device geometry and material parameters. Three micromachined lateral resonant resonators with different beam widths were fabricated. Their resonant frequencies were experimentally measured to be 64.5,147.2, and 255.5kHz, respectively, which are in good agreement with the simulated resonant frequency. It is shown that an improved frequency performance could be obtained on the poly 3C-SiC based device structural material systems with high Young＇s modulus.展开更多
A compact spectrometer on silicon is proposed and demonstrated with an ultrahigh resolution.It consists of a thermally-tunable ultra-high-Q resonator aiming at ultrahigh resolution and an array of wideband resonators ...A compact spectrometer on silicon is proposed and demonstrated with an ultrahigh resolution.It consists of a thermally-tunable ultra-high-Q resonator aiming at ultrahigh resolution and an array of wideband resonators for achieving a broadened working window.The present on-chip spectrometer has a footprint as compact as 0.35 mm^(2),and is realized with standard multi-project-wafer foundry processes.The measurement results show that the on-chip spectrometer has an ultra-high resolution Δλ of 5 pm and a wide working window of 10 nm.The dynamic range defined as the ratio of the working window and the wavelength resolution is as large as 1940,which is the largest for on-chip dispersive spectro-meters to the best of our knowledge.The present high-performance on-chip spectrometer has great potential for high-resolution spectrum measurement in the applications of gas sensing,food monitoring,health analysis,etc.展开更多
The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial developm...The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (<em>D</em>(<em>ω</em>, <em>B</em>), in the (<em>p</em>) base leads to maximum values (Dmax) at resonance frequencies (<em>ωr</em>). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, <em>ωr</em> and <em>B</em>, are then established, and will be data for industrial development of low-cost solar cells for specific use.展开更多
We experimentally demonstrate a small-size and high-speed silicon optical switch based on the free carrier plasma dispersion in silicon. Using an embedded racetrack resonator with a quality factor of 7400, the optical...We experimentally demonstrate a small-size and high-speed silicon optical switch based on the free carrier plasma dispersion in silicon. Using an embedded racetrack resonator with a quality factor of 7400, the optical switch shows an extinction ratio exceeding 13 dB with a footprint of only 2.2 × 10-3 mm^2. Moreover, a novel pre-emphasis technique is introduced to improve the optical response performance and the rise and the fall times are reduced down to 0.24 ns and 0.42 ns respectively, which are 25% and 44% lower than those without the pre-emphasis.展开更多
To further research the response of the tearing mode（TM） to dynamic resonant magnetic perturbation（DRMP） on the J-TEXT tokamak, a modified series resonant inverter power supply（MSRIPS） with a function of discret...To further research the response of the tearing mode（TM） to dynamic resonant magnetic perturbation（DRMP） on the J-TEXT tokamak, a modified series resonant inverter power supply（MSRIPS） with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor（IGBT） full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier（SCR） switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.展开更多
Silicon nitride(Si3N4)waveguides with high confinement and low loss have been widely used in integrated nonlinear photonics.Indeed,state-of-the-art ultralow-loss Si3N4 waveguides are all fabricated using complex fabri...Silicon nitride(Si3N4)waveguides with high confinement and low loss have been widely used in integrated nonlinear photonics.Indeed,state-of-the-art ultralow-loss Si3N4 waveguides are all fabricated using complex fabrication processes,and all of those reported that high Q microring resonators(MRRs)are fabricated in laboratories.We propose and demonstrate an ultralow-loss Si3N4 racetrack MRR by shaping the mode using a uniform multimode structure to reduce its overlap with the waveguide.The MRR is fabricated by the standard multi project wafer(MPW)foundry process.It consists of two multimode straight waveguides(MSWs)connected by two multimode waveguide bends(MWBs).In particular,the MWBs are based on modified Euler bends,and an MSW directional coupler is used to avoid higher-order mode excitation.In this way,although a multimode waveguide is used in the MRR,only the fundamental mode is excited and transmitted with ultralow loss.Meanwhile,thanks to the 180 deg Euler bend,a compact chip footprint of 2.226 mm perimeter with an effective radius as small as 195μm and a waveguide width of 3μm is achieved.Results show that based on the widely used MPW process,a propagation loss of only 3.3 dB∕m and a mean intrinsic Q of around 10.8 million are achieved for the first time.展开更多
We designed a reconfigurable dual-interferometer coupled silicon nitride microring resonator.By tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is c...We designed a reconfigurable dual-interferometer coupled silicon nitride microring resonator.By tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9×10^(4) to 1.9×10^(5) with the extinction ratio keeping higher than 25 dB.Also a variety of coupling spanning from"under-coupling"to"over-coupling"were achieved,showing the ability to tune the quality factor from 6.0×10^(3) to 2.3×10^(5).Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.展开更多
A nonlinear integrated optical platform that allows the fabrication of waveguide circuits with different material composition,and at small dimensions,offers advantages in terms of field enhancement and increased inter...A nonlinear integrated optical platform that allows the fabrication of waveguide circuits with different material composition,and at small dimensions,offers advantages in terms of field enhancement and increased interaction length,thereby facilitating the observation of nonlinear optics effects at a much lower power level.To enhance the nonlinearity of the conventional waveguide structure,in this work,we propose and demonstrate a microstructured waveguide where silicon rich layer is embedded in the core of the conventional waveguide in order to increase its nonlinearity.By embedding a 20 nm thin film of silicon nanocrystal(Si-nc),we achieve a twofold increase of the nonlinear parameter,γ.The linear relationship between the fourwave mixing conversion efficiency and pump power reveals the negligible nonlinear absorption and small dispersion in the micro-ring resonators.This simple approach of embedding an ultra-thin Si-nc layer into conventional high-index doped silica dramatically increases its nonlinear performance,and could potentially find applications in all-optical processing functions.展开更多
High-dimensional entanglement provides valuable resources for quantum technologies,including quantum communication,quantum optical coherence tomography,and quantum computing.Obtaining a high brightness and dimensional...High-dimensional entanglement provides valuable resources for quantum technologies,including quantum communication,quantum optical coherence tomography,and quantum computing.Obtaining a high brightness and dimensional entanglement source has significant value.Here we utilize a tunable asymmetric Mach–Zehnder interferometer coupled silicon microring resonator with 100 GHz free spectral range to achieve this goal.With the strategy of the tunable coupler,the dynamical and extensive tuning range of quality factors of the microring can be obtained,and then the biphoton pair generation rate can be optimized.By selecting and characterizing 28 pairs from a more than 30-pair modes biphoton frequency comb,we obtain a Schmidt number of at least 23.4 and on-chip pair generation rate of 19.9 MHz/m W;under a low on-chip pump power,which corresponds to 547 dimensions Hilbert space in frequency freedom.These results will prompt the wide applications of quantum frequency comb and boost the further large density and scalable on-chip quantum information processing.展开更多
This study focuses on the mechanical response of silicon on porous silicon bilayer cantilevers ended with a seismic mass. The porous silicon is intended to provide an alternative to decrease the cantilever stiffness f...This study focuses on the mechanical response of silicon on porous silicon bilayer cantilevers ended with a seismic mass. The porous silicon is intended to provide an alternative to decrease the cantilever stiffness for low-frequency MEMS applications. The first eigenfrequency of the cantilever is obtained using static deflection obtained under classical Euler-Bernoulli assumptions and Rayleigh method. In order to estimate the errors due to small-strain approximation and Euler-Bernoulli theory, the analytical results were validated through 3D finite element simulations for different cantilever geometries and porosities. Both bulk silicon and silicon on porous silicon bilayer cantilevers ended with a seismic mass were fabricated and we measured the first eigenfrequency (f0) and quality factor (Q) by using a laser Doppler vibrometer. In agreement with the theoretical predictions we found that, when compared to bulk silicon cantilevers, the first eigenfrequency of a bilayer cantilever containing 6% porous silicon (at 50% porosity) on 94% bulk silicon is lowered by 5%, from (5447 ±120) Hz to ≈5198 Hz. This decrease is also accompanied by a reduction of the quality factor by two.展开更多
A high-performance microring resonator in a silicon-on-insulator rib waveguide is realized by using the electron beam lithography followed by inductively coupled plasma etching. The design and the experimental realiza...A high-performance microring resonator in a silicon-on-insulator rib waveguide is realized by using the electron beam lithography followed by inductively coupled plasma etching. The design and the experimental realization of this device are presented in detail. In addition to improving relevant processes to minimize propagation loss, the coupling efficiency between the ring and the bus is carefully chosen to approach a critical coupling for high performance operating. We have measured a quality factor of 21,200 and an extinction ratio of 12.SdB at a resonant wavelength of 1549.32nm. Meanwhile, a low propagation loss of 0.89dB/mm in a curved waveguide with a bending radius of 40μm is demonstrated as well.展开更多
We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simu- lations using the three-dimensional finite-difference time-domain method show that the novel elliptical m...We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simu- lations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.展开更多
Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg bound.In particular,quantum probes prepared in nonclassical coherent states have recently ...Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg bound.In particular,quantum probes prepared in nonclassical coherent states have recently been recognized as a useful resource for metrology.Hence,there has been considerable interest in constructing magnetic quantum sensors that combine high resolution and high sensitivity.Here,we explore a nanoscale magnetometer with quantum-enhanced sensitivity,based on 123Sb(I=7/2)nuclear spin doped in silicon,that takes advantage of techniques of spin-squeezing and coherent control.With the optimal squeezed initial state,the magnetic field sensitivity may be expected to approach 6 aT·Hz^(−1/2)·cm^(−3/2) and 603 nT·Hz^(−1/2) at the single-spin level.This magnetic sensor may provide a novel sensitive and high-resolution route to microscopic mapping of magnetic fields as well as other applications.展开更多
To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes ...To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.展开更多
The working principle of silicon micro-resonator system was firstly introduced. An intelligent silicon micro-resonator system design and realization was presented in focus. There are two steps working flows for roughn...The working principle of silicon micro-resonator system was firstly introduced. An intelligent silicon micro-resonator system design and realization was presented in focus. There are two steps working flows for roughness and fine searching. Meanwhile the digital interface technology was analyzed in detail. Combined with experimental data and sweeping curve, two different searching results came out in different vacuum circumstance and its working performance was well evaluated.展开更多
基金The Chinese Aeronautics Science Foundation(99I5 10 0 6)Foundation for University Key Teacherby the Ministry of Education
文摘According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operating mechanism is analyzed. The thermal resistor acts as the excited unit, and the piezoresistive unit acts as the detector, for the above micro sensor. By using the amplitude and phase conditions, the self exciting closed loop system is investigated based on the operating mechanism for the abov...
基金Project supported by the National Natural Science Foundation of China(Grant No.41075026)the Open Research Fund of Key Laboratory of MEMS of Ministry of Education,Southeast University,China(Grant Nos.2009-03 and 2010-02)+2 种基金the SpecialFund for Meteorology Research in the Public Interest,China(Grant No.GYHY200906037)the Priority Academic ProgramDevelopment of Sensor NetworksModern Meteorological Equipment of Jiangsu Higher Education Institutions,China
文摘The purpose of the present work is to quantify the influences of the discrete nature, the surface effects, and the large deformation on the bending resonant properties of long and ultrathin （100） silicon nanocantilevers. We accomplish this by using an analytical semi-continuum Keating model within the framework of nonlinear, finite deformation kinematics. The semi-continuum model shows that the elastic behaviors of the silicon nanocantilevers are size-dependent and surface- dependent, which agrees well with the molecular dynamics results. It also indicates that the dominant effect on the fundamental resonant frequency shift of the silicon nanocantilever is adsorption-induced surface stress, followed by the discrete nature and surface reconstruction, whereas surface relaxation has the least effect. In particular, it is found that a large deformation tends to increase the nonlinear fundamental frequency of the silicon nanocantilever, depending not only on its size but also on the surface effects. Finally, the resonant frequency shifts due to the adsorption-induced surface stress predicted by the current model are quantitatively compared with those obtained from the experimental measurement and the other existing approach. It is noticed that the length-to-thickness ratio is the key parameter that correlates the deviations in the resonant frequencies predicted from the current model and the empirical formula.
文摘Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency drift as we adjusted the device geometry and material parameters. Three micromachined lateral resonant resonators with different beam widths were fabricated. Their resonant frequencies were experimentally measured to be 64.5,147.2, and 255.5kHz, respectively, which are in good agreement with the simulated resonant frequency. It is shown that an improved frequency performance could be obtained on the poly 3C-SiC based device structural material systems with high Young＇s modulus.
基金financial supports from National Major Research and Development Program(No.2018YFB2200200)National Science Fund for Distinguished Young Scholars(61725503)+2 种基金National Natural Science Foundation of China(NSFC)(6191101294,91950205)Zhejiang Provincial Natural Science Foundation(LZ18F050001,LD19F050001)The Fundamental Research Funds for the Central Universities.Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2021R01001).
文摘A compact spectrometer on silicon is proposed and demonstrated with an ultrahigh resolution.It consists of a thermally-tunable ultra-high-Q resonator aiming at ultrahigh resolution and an array of wideband resonators for achieving a broadened working window.The present on-chip spectrometer has a footprint as compact as 0.35 mm^(2),and is realized with standard multi-project-wafer foundry processes.The measurement results show that the on-chip spectrometer has an ultra-high resolution Δλ of 5 pm and a wide working window of 10 nm.The dynamic range defined as the ratio of the working window and the wavelength resolution is as large as 1940,which is the largest for on-chip dispersive spectro-meters to the best of our knowledge.The present high-performance on-chip spectrometer has great potential for high-resolution spectrum measurement in the applications of gas sensing,food monitoring,health analysis,etc.
文摘The modelling and determination of the geometric parameters of a solar cell are important data, which influence the evaluation of its performance under specific operating conditions, as well as its industrial development for a low cost. In this work, an n+/p/p+ crystalline silicon solar cell is studied under monochromatic illumination in modulation and placed in a constant magnetic field. The minority carriers’ diffusion coefficient (<em>D</em>(<em>ω</em>, <em>B</em>), in the (<em>p</em>) base leads to maximum values (Dmax) at resonance frequencies (<em>ωr</em>). These values are used in expressions of AC minority carriers recombination velocity (Sb(Dmax, H)) in the rear of the base, to extract the optimum thickness while solar cell is subjected to these specific conditions. Optimum thickness modelling relationships, depending respectively on Dmax, <em>ωr</em> and <em>B</em>, are then established, and will be data for industrial development of low-cost solar cells for specific use.
基金Project supported by the National Natural Science Foundation of China(Grant No.60877036)the National Basic Research Program of China(Grant No.2006CB302803)+1 种基金the State Key Laboratory of Advanced Optical Communication Systems and Networks,China(Grant No.2008SH02)the Knowledge Innovation Program of Institute of Semiconductors,Chinese Academy of Sciences(Grant No.ISCAS2008T10)
文摘We experimentally demonstrate a small-size and high-speed silicon optical switch based on the free carrier plasma dispersion in silicon. Using an embedded racetrack resonator with a quality factor of 7400, the optical switch shows an extinction ratio exceeding 13 dB with a footprint of only 2.2 × 10-3 mm^2. Moreover, a novel pre-emphasis technique is introduced to improve the optical response performance and the rise and the fall times are reduced down to 0.24 ns and 0.42 ns respectively, which are 25% and 44% lower than those without the pre-emphasis.
基金supported by the National ITER Project Foundation of China(No.2014GB118000)National Natural Science Foundation of China(No.11405068)
文摘To further research the response of the tearing mode（TM） to dynamic resonant magnetic perturbation（DRMP） on the J-TEXT tokamak, a modified series resonant inverter power supply（MSRIPS） with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor（IGBT） full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier（SCR） switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.
基金supported by the National Natural Science Foundation of China(Grant No.61975249)the National Key Research and Development Program of China(Grant No.2018YFA0704403)the Program for HUST Academic Frontier Youth Team(Grant No.2018QYTD08).
文摘Silicon nitride(Si3N4)waveguides with high confinement and low loss have been widely used in integrated nonlinear photonics.Indeed,state-of-the-art ultralow-loss Si3N4 waveguides are all fabricated using complex fabrication processes,and all of those reported that high Q microring resonators(MRRs)are fabricated in laboratories.We propose and demonstrate an ultralow-loss Si3N4 racetrack MRR by shaping the mode using a uniform multimode structure to reduce its overlap with the waveguide.The MRR is fabricated by the standard multi project wafer(MPW)foundry process.It consists of two multimode straight waveguides(MSWs)connected by two multimode waveguide bends(MWBs).In particular,the MWBs are based on modified Euler bends,and an MSW directional coupler is used to avoid higher-order mode excitation.In this way,although a multimode waveguide is used in the MRR,only the fundamental mode is excited and transmitted with ultralow loss.Meanwhile,thanks to the 180 deg Euler bend,a compact chip footprint of 2.226 mm perimeter with an effective radius as small as 195μm and a waveguide width of 3μm is achieved.Results show that based on the widely used MPW process,a propagation loss of only 3.3 dB∕m and a mean intrinsic Q of around 10.8 million are achieved for the first time.
基金the National Key Research and Development Program of China(Grant Nos.2019YFA0308700and 2017YFA0303700)the National Natural Science Foundation of China(Grant Nos.11627810 and 11690031)the Open Funds from the State Key Laboratory of High Performance Computing of China(HPCL,National University of Defense Technology).
文摘We designed a reconfigurable dual-interferometer coupled silicon nitride microring resonator.By tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9×10^(4) to 1.9×10^(5) with the extinction ratio keeping higher than 25 dB.Also a variety of coupling spanning from"under-coupling"to"over-coupling"were achieved,showing the ability to tune the quality factor from 6.0×10^(3) to 2.3×10^(5).Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.
基金the Research Grants Council,University Grants Committee(GRF 11213618)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB24030300).
文摘A nonlinear integrated optical platform that allows the fabrication of waveguide circuits with different material composition,and at small dimensions,offers advantages in terms of field enhancement and increased interaction length,thereby facilitating the observation of nonlinear optics effects at a much lower power level.To enhance the nonlinearity of the conventional waveguide structure,in this work,we propose and demonstrate a microstructured waveguide where silicon rich layer is embedded in the core of the conventional waveguide in order to increase its nonlinearity.By embedding a 20 nm thin film of silicon nanocrystal(Si-nc),we achieve a twofold increase of the nonlinear parameter,γ.The linear relationship between the fourwave mixing conversion efficiency and pump power reveals the negligible nonlinear absorption and small dispersion in the micro-ring resonators.This simple approach of embedding an ultra-thin Si-nc layer into conventional high-index doped silica dramatically increases its nonlinear performance,and could potentially find applications in all-optical processing functions.
基金supported by the National Basic Research Program of China(Grant Nos.2019YFA0308700 and 2017YFA0303700)the National Natural Science Foundation of China(Grant Nos.61632021 and 11690031)the Open Funds from the State Key Laboratory of High Performance Computing of China(HPCL,National University of Defense Technology)。
文摘High-dimensional entanglement provides valuable resources for quantum technologies,including quantum communication,quantum optical coherence tomography,and quantum computing.Obtaining a high brightness and dimensional entanglement source has significant value.Here we utilize a tunable asymmetric Mach–Zehnder interferometer coupled silicon microring resonator with 100 GHz free spectral range to achieve this goal.With the strategy of the tunable coupler,the dynamical and extensive tuning range of quality factors of the microring can be obtained,and then the biphoton pair generation rate can be optimized.By selecting and characterizing 28 pairs from a more than 30-pair modes biphoton frequency comb,we obtain a Schmidt number of at least 23.4 and on-chip pair generation rate of 19.9 MHz/m W;under a low on-chip pump power,which corresponds to 547 dimensions Hilbert space in frequency freedom.These results will prompt the wide applications of quantum frequency comb and boost the further large density and scalable on-chip quantum information processing.
文摘This study focuses on the mechanical response of silicon on porous silicon bilayer cantilevers ended with a seismic mass. The porous silicon is intended to provide an alternative to decrease the cantilever stiffness for low-frequency MEMS applications. The first eigenfrequency of the cantilever is obtained using static deflection obtained under classical Euler-Bernoulli assumptions and Rayleigh method. In order to estimate the errors due to small-strain approximation and Euler-Bernoulli theory, the analytical results were validated through 3D finite element simulations for different cantilever geometries and porosities. Both bulk silicon and silicon on porous silicon bilayer cantilevers ended with a seismic mass were fabricated and we measured the first eigenfrequency (f0) and quality factor (Q) by using a laser Doppler vibrometer. In agreement with the theoretical predictions we found that, when compared to bulk silicon cantilevers, the first eigenfrequency of a bilayer cantilever containing 6% porous silicon (at 50% porosity) on 94% bulk silicon is lowered by 5%, from (5447 ±120) Hz to ≈5198 Hz. This decrease is also accompanied by a reduction of the quality factor by two.
基金supported by the State Key Development Program for Basic Research of China (Grant Nos 2006CB302803 and2007CB613405)the National High Technology Research and Development Program of China (Grant No 2006AA03Z424)the National Natural Science Foundation of China (Grant No 60577044)
文摘A high-performance microring resonator in a silicon-on-insulator rib waveguide is realized by using the electron beam lithography followed by inductively coupled plasma etching. The design and the experimental realization of this device are presented in detail. In addition to improving relevant processes to minimize propagation loss, the coupling efficiency between the ring and the bus is carefully chosen to approach a critical coupling for high performance operating. We have measured a quality factor of 21,200 and an extinction ratio of 12.SdB at a resonant wavelength of 1549.32nm. Meanwhile, a low propagation loss of 0.89dB/mm in a curved waveguide with a bending radius of 40μm is demonstrated as well.
基金Project supported by the National Basic Research Program of China (Grant Nos. 2011CB301701, 2012CB933502, and2012CB933504)the National Natural Science Foundation of China (Grant Nos. 60877036 and 61107048)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KGCX2-EW-102)
文摘We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simu- lations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.
基金the National Natural Science Foundation of China(Grant Nos.1212200199,12122506,12004165,12275117,and 12204230)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021B1515020070 and 2022B1515020074)+1 种基金Guangdong Provincial Key Laboratory(Grant No.2019B121203002)Shen-zhen Science and Technology Program(Grant Nos.KQTD20200820113010023,RCBS20200714114820298,and RCYX20200714114522109).
文摘Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg bound.In particular,quantum probes prepared in nonclassical coherent states have recently been recognized as a useful resource for metrology.Hence,there has been considerable interest in constructing magnetic quantum sensors that combine high resolution and high sensitivity.Here,we explore a nanoscale magnetometer with quantum-enhanced sensitivity,based on 123Sb(I=7/2)nuclear spin doped in silicon,that takes advantage of techniques of spin-squeezing and coherent control.With the optimal squeezed initial state,the magnetic field sensitivity may be expected to approach 6 aT·Hz^(−1/2)·cm^(−3/2) and 603 nT·Hz^(−1/2) at the single-spin level.This magnetic sensor may provide a novel sensitive and high-resolution route to microscopic mapping of magnetic fields as well as other applications.
基金supported by Natural Science Foundation of Gansu Province(No.22JR5RA320).
文摘To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.
基金The National High Technology Research and Development Programof China(863 Program)(No.2002AA812038) The National Defense Pre-research Support Program(No.41308050109)
文摘The working principle of silicon micro-resonator system was firstly introduced. An intelligent silicon micro-resonator system design and realization was presented in focus. There are two steps working flows for roughness and fine searching. Meanwhile the digital interface technology was analyzed in detail. Combined with experimental data and sweeping curve, two different searching results came out in different vacuum circumstance and its working performance was well evaluated.
