Optical whispering gallery mode （WGM） microresonators have attracted great attention due to their remarkable proper- ties such as extremely high quality factor, small mode volume, tight confinement of modes, and str...Optical whispering gallery mode （WGM） microresonators have attracted great attention due to their remarkable proper- ties such as extremely high quality factor, small mode volume, tight confinement of modes, and strong evanescent field. All these properties of WGM microresonators have ensured their great potentials for applications, such as physical sen- sors, bio/chemical sensors and microlasers. In this mini-review, the key parameters and coupling conditions of WGM microresonators are firstly introduced. The geometries of WGM optical microcavities are presented based on their fabri- cation methods. This is followed by the discussion on the state-of-the-art applications of WGM microresonators in sen- sors and microlasers.展开更多
The design of thermoelastic damping(TED)affected by the phase-lagging non-Fourier heat conduction effects becomes significant but challenging for enlarging the quality factor of widely-used microresonators operating i...The design of thermoelastic damping(TED)affected by the phase-lagging non-Fourier heat conduction effects becomes significant but challenging for enlarging the quality factor of widely-used microresonators operating in extreme situations,including ultra-high excitation frequency and ultra-low working temperature.However,there does not exist a rational method for designing the TED in the framework of non-Fourier heat conduction law.This work,therefore,proposes a design framework to achieve low thermoelastic dissipation of microresonators governed by the phase-lagging heat conduction law.The equation of motion and the heat conduction equation for phase-lagging TED microresonators are derived first,and then the non-Fourier TED design problem is proposed.A topology optimization-based rational design method is used to resolve the design problem.What is more,a two-dimensional(2D)plain-strain-based finite element method(FEM)is developed as a solver for the topology optimization process.Based on the suggested rational design technique,numerical instances with various phase lags are investigated.The results show that the proposed design method can remarkably reduce the dissipation of microresonators by tailoring their substructures.展开更多
In superconducting circuit,microwave resonators and capacitors are crucial components,and their quality has a strong impact on circuit performance.Here we develop a novel wet etching process to define these two compon...In superconducting circuit,microwave resonators and capacitors are crucial components,and their quality has a strong impact on circuit performance.Here we develop a novel wet etching process to define these two components using common photoresist developer as etchant.This method reduces subsequent steps and can be completed immediately after development.By measuring the internal quality factor of resonators,we show that it is possible to achieve similar or better performance when compared with samples made by standard etching processes.This easy-to-implement method may boost the yield hence providing an alternative fabrication process for microwave resonators and capacitors.展开更多
We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emi...We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emitter. Quantum routing probability in the output port is obtained via the real-space Hamiltonian. By adjusting the resonator–emitter coupling and the drive, the desired continuous central frequencies for the resonance peaks of routing photons can be manipulated nearly linearly, with the assistance of Rabi splitting effect and optical Stark shift. The proposed routing system may provide potential applications in designing other frequency-modulation quantum optical devices, such as multiplexers,filters, and so on.展开更多
The ring microresonator filter considering resonator inner loss is analyzed theoretically, which has one input port and two output ports. Some universal relations for coupling of optical power between microresonator a...The ring microresonator filter considering resonator inner loss is analyzed theoretically, which has one input port and two output ports. Some universal relations for coupling of optical power between microresonator and dielectric waveguides are presented. The analytical expressions of filter bandwidth or the full width at half maximum(FWHM), free spectral range and finesse of resonator are derived. The characteristics of the ring microresonator filter are discussed numerically. It is demonstrated that the loss of the ring resonator reduces the peak value of transmission, widens the filter bandwidth, and reduces the finesse of the resonator filter.展开更多
A 4.13 MHz reference oscillator incorporating a capacitive single-crystal-silicon （SCS） micromechanical resonator is presented. The microresonator is fabricated using a cavity silicon-on-insulator （cavity-SOl） pro...A 4.13 MHz reference oscillator incorporating a capacitive single-crystal-silicon （SCS） micromechanical resonator is presented. The microresonator is fabricated using a cavity silicon-on-insulator （cavity-SOl） process and is excited in the Lain6 mode with electrostatic driving and capacitive sensing. The Lam6 mode may be described as a square plate that is cont- racting along one axis in the fabrication plane, while simultaneously extending along an orthogonal axis in the same plane. The microresonator exhibits a quality factor as high as 1.4 × 10^6 and a resonant frequency of 4.13 MHz at a pressure of 0.08 mbar. The output spectrum of the oscillator shows that the silicon micromechanical resonator is adapted as a timing element for a precision oscillator.展开更多
To improve the performance and reliability of microelectromechanical system＇s devices, it is necessary to understand the effect of friction which exists in the majority of microelectromechanical systems （MEMS） with...To improve the performance and reliability of microelectromechanical system＇s devices, it is necessary to understand the effect of friction which exists in the majority of microelectromechanical systems （MEMS） with a large ratio of surface area to their volume. The model of electrostatic tangential force of the shuttle in laterally driven comb microresonator is established based on the rule of energy conservation. The effects of microscale, surface roughness, applied voltage, and micro asperities or dents or holes formed in fabrication are investigated, and the electrostatic resistance between two charged moving plates is analyzed. The analytic results are coincident well with those of ANSYS simulation. It is found that the electrostatic resistance becomes high as the increase of the ratio of the shuttle width to the gap between moving plates and the relative surface roughness or the increment of the applied voltage.展开更多
We have suggested a novel multiport quantum router of single photons with reflection feedback, which is formed by three waveguides coupled with four single-mode microresonators. The single-photon routing probabilities...We have suggested a novel multiport quantum router of single photons with reflection feedback, which is formed by three waveguides coupled with four single-mode microresonators. The single-photon routing probabilities of four channels in the coupled system are studied theoretically by applying the real-space approach. Numerical results indicate that unidirectional routing in these output channels can be effectively implemented, and the router is tunable to route desired frequencies into the output ports, by varying the inter-resonator detunings via spinning resonator technology. Therefore, the proposed multichannel system can provide potential applications in optical quantum communication.展开更多
Microresonator dispersion plays a crucial role in shaping the nonlinear dynamics of microcavity solitons.Here,we introduce and validate a method for dispersion engineering through modulating a portion of the inner edg...Microresonator dispersion plays a crucial role in shaping the nonlinear dynamics of microcavity solitons.Here,we introduce and validate a method for dispersion engineering through modulating a portion of the inner edge of ring waveguides.We demonstrate that such partial modulation has a broadband effect on the dispersion profile,whereas modulation on the entire resonator's inner circumference leads to mode splitting primarily affecting one optical mode.The impact of spatial modulation amplitude,period,and number of modulations on the mode splitting profile is also investigated.Through the integration of four modulated sections with different modulation amplitudes and periods,we achieve mode splitting across more than 50 modes over a spectral range exceeding 100 nm in silicon nitride resonators.These results highlight both the simplicity and efficacy of our method in achieving flatter dispersion profiles.展开更多
Chip-based optical microresonators with ultra-high Q-factors are becoming increasingly important to a variety of applications. However, the losses of on-chip microresonators with the highest Q-factor reported in the p...Chip-based optical microresonators with ultra-high Q-factors are becoming increasingly important to a variety of applications. However, the losses of on-chip microresonators with the highest Q-factor reported in the past are still far from their material absorption limits. Here, we demonstrate an on-chip silica microresonator that has approached the absorption limit of the state-of-the-art material on chip, realizing, to our knowledge, record intrinsic Q-factors exceeding 3 billion at both 1560 nm and 1064 nm. This fact is corroborated by photo-thermal spectroscopy measurements. Especially, compared with the standard optical fibers, its corresponding optical losses are only 38.4 times and 7.7 times higher at the wavelengths of 1560 nm and 1064 nm, respectively.To exhibit the performance of such fabricated microresonator, we achieve a record-low optical parametric oscillation threshold(31.9 μW) for millimeter-sized microresonators and generate a single-soliton microcomb with a record-low pump power of 220.2 μW for all soliton microcombs realized thus far.展开更多
With the rapid development of the Internet of Things and big data,integrated optical switches are gaining prominence for applications in on-chip optical computing,optical memories,and optical communications.Here,we pr...With the rapid development of the Internet of Things and big data,integrated optical switches are gaining prominence for applications in on-chip optical computing,optical memories,and optical communications.Here,we propose a novel approach for on-chip optical switches by utilizing the nonlinear optical Kerr effect induced spontaneous symmetry breaking(SSB),which leads to two distinct states of counterpropagating light in ring resonators.This technique is based on our first experimental observation of on-chip symmetry breaking in a high-Q(9.4×10~6)silicon nitride resonator with a measured SSB threshold power of approximately 3.9 mW.We further explore the influence of varying pump powers and frequency detunings on the performance of SSB-induced optical switches.Our work provides insights into the development of new types of photonic data processing devices and provides an innovative approach for the future implementation of on-chip optical memories.展开更多
We report on second harmonic generation(SHG) in on-chip high-Q(>105) lithium niobate(Li Nb O3, LN) microresonators fabricated by femtosecond laser micromachining. We examine the efficiency of SHG with either a cont...We report on second harmonic generation(SHG) in on-chip high-Q(>105) lithium niobate(Li Nb O3, LN) microresonators fabricated by femtosecond laser micromachining. We examine the efficiency of SHG with either a continuous-wave(CW) or an ultrashort pulsed pump laser. The normalized conversion efficiencies of SHG obtained with the CW and pulsed pump lasers are measured to be 1.35×10?5 m W?1 and 2.30×10?6 m W?1, respectively.展开更多
The stabilization and manipulation of laser frequency by means of an external cavity are nearly ubiquitously used in fundamental research and laser applications. While most of the laser light transmits through the cav...The stabilization and manipulation of laser frequency by means of an external cavity are nearly ubiquitously used in fundamental research and laser applications. While most of the laser light transmits through the cavity, in the presence of some back-scattered light from the cavity to the laser, the self-injection locking effect can take place, which locks the laser emission frequency to the cavity mode of similar frequency. The self-injection locking leads to dramatic reduction of laser linewidth and noise. Using this approach, a common semiconductor laser locked to an ultrahigh-Q microresonator can obtain sub-Hertz linewidth, on par with state-of-the-art fiber lasers. Therefore it paves the way to manufacture high-performance semiconductor lasers with reduced footprint and cost. Moreover, with high laser power, the optical nonlinearity of the microresonator drastically changes the laser dynamics, offering routes for simultaneous pulse and frequency comb generation in the same microresonator. Particularly, integrated photonics technology, enabling components fabricated via semiconductor CMOS process, has brought increasing and extending interest to laser manufacturing using this method. In this article, we present a comprehensive tutorial on analytical and numerical methods of laser self-injection locking, as well a review of most recent theoretical and experimental achievements.展开更多
Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and prov...Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and provide mode-selection capability.In this work,by engineering the pump intensity to modify the spatial gain profiles of bottle microresonators,we demonstrate a simple and general approach to realizing single-mode WGM lasing in polymer bottle microresonators.The pump intensity is engineered into an interference distribution on the bottle microresonator surface.By tuning the spacing between axial positions of the interference pump patterns,the mode intensity profiles of single-bottle WGMs can be spatially overlapped with the interference stripes,intrinsically enabling single-mode lasing and selection.Attractive advantages of the system,including high sidemode suppression factors 420 dB,large spectral tunability 48 nm,low-lasing threshold and reversible control,are presented.Our demonstrated approach may have a variety of promising applications,ranging from tunable single-mode lasing and sensing to nonlinear optics.展开更多
On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton q...On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton quantum source with spectral multiplexing generated in a lithium niobate microresonator system.Without introducing the conventional domain poling,the on-chip microdisk produces photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion.Experimentally,the multiplexed photon pairs are characterized by 30 nm bandwidth limited by the filtering system,providing over 40 multiplexing channels with a 0.8 nm channel spacing.Meanwhile,the generation rate reaches 5.13 MHz/μW with a coincidence-to-accidental ratio up to 804,and the quantum source manifests a high purity with a heralded single photon correlation g^((2))_(H)(0)=0.0098±0.0021.Furthermore,the energy-time entanglement is demonstrated with an excellent interference visibility of 96.5%±2%.Such a quantum source at the telecommunication band paves the way for high-dimensional entanglement and future integrated quantum information systems.展开更多
The microresonator-based soliton microcomb has shown a promising future in many applications.In this work,we report the fabrication of high quality[Q]Si_(3)N_(4)microring resonators for soliton microcomb generation.By...The microresonator-based soliton microcomb has shown a promising future in many applications.In this work,we report the fabrication of high quality[Q]Si_(3)N_(4)microring resonators for soliton microcomb generation.By developing the fabri-cation process with crack isolation trenches and annealing,we can deposit thick stoichiometric Si3N4 film of 800 nm without cracks in the central area.The highest intrinsic Q of the Si_(3)N_(4)microring obtained in our experiments is about 6×10^(6),corresponding to a propagation loss as low as 0.058 dBm/cm.With such a high Q film,we fabricate microrings with the anomalous dispersion and demonstrate the generation of soliton microcombs with 100 mW on-chip pump power,with an optical parametric oscillation threshold of only 13.4 mW.Our Si_(3)N_(4)integrated chip provides an ideal platform for researches and applications of nonlinear photonics and integrated photonics.展开更多
We have reported the high-Q whispering gallery modes(WGMs) in a polydimethylsiloxane(PDMS) optical microresonators with broad tuning range. The PDMS microresonators are fabricated at the center of two collimating fibe...We have reported the high-Q whispering gallery modes(WGMs) in a polydimethylsiloxane(PDMS) optical microresonators with broad tuning range. The PDMS microresonators are fabricated at the center of two collimating fiber tips, which can be controlled by the piezoelectric stage. Through stretching the fiber stem, the tuning range of WGMs are demonstrated more than 50 nm.Further investigations demonstrated that the WGM shift has a high force sensitivity(～ 19.7 pm/μN) of the gravitation when the microcavity is stretched by a weight. The theoretical analysis reveals that the high force sensitivity of polymer microresonator can be used for the weak force or height measurement.展开更多
Second-order(χ^((2))) optical nonlinearity is one of the most common mechanisms for modulating and generating coherent light in photonic devices.Due to strong photon confnement and long photon lifetime,integrated mic...Second-order(χ^((2))) optical nonlinearity is one of the most common mechanisms for modulating and generating coherent light in photonic devices.Due to strong photon confnement and long photon lifetime,integrated microresonators have emerged as an ideal platform for investigation of nonlinear optical efects.However,existing silicon-based materials lack a χ^((2)) response due to their centrosymmetric structures.A variety of novel material platforms possessing χ^((2)) nonlinearity have been developed over the past two decades.This review comprehensively summarizes the progress of second-order nonlinear optical efects in integrated microresonators.First,the basic principles of χ^((2)) nonlinear efects are introduced.Afterward,we highlight the commonly used χ^((2)) nonlinear optical materials,including their material properties and respective functional devices.We also discuss the prospects and challenges of utilizing χ^((2)) nonlinearity in the feld of integrated microcavity photonics.展开更多
Microresonator frequency combs （microcombs） are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the s...Microresonator frequency combs （microcombs） are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the study of microcombs to reveal and control the comb formation dynamics. In this paper, we reviewed the microwave photonic techniques and applications that are connected with microcombs. The future research directions of microcomb-based microwave photonics were also discussed.展开更多
We demonstrate high-quality(intrinsic Q factor∼2.8×106)racetrack microresonators fabricated on lithium niobate thin film with a free spectral range(FSR)of∼86 pm.By integrating microelectrodes alongside the two ...We demonstrate high-quality(intrinsic Q factor∼2.8×106)racetrack microresonators fabricated on lithium niobate thin film with a free spectral range(FSR)of∼86 pm.By integrating microelectrodes alongside the two straight arms of the racetrack resonator,the resonance wavelength around 1550 nm can be red shifted by 92 pm when the electric voltage is raised from−100 V to 100 V.The microresonators with the tuning range spanning over a full FSR are fabricated using photolithography assisted chemo-mechanical etching.展开更多
基金This work is partially supported by National Natural Science Foundation of China （11774102）, the Scientific Research Funds and Promotion Program for Young and Middle-aged Teacher in Science ＆ Technology Research of Huaqiao University （ZQN-YXS04, 17BS412）, Open Fund of IPOC （BUPT）, National Research Foundation Singapore （NRF） （NRF-CRP13-2014-05）, European Union＇s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement （No. 798916） and Singapore Ministry of Education Academic Research Fund Tier 1 （RG89/16）.
文摘Optical whispering gallery mode （WGM） microresonators have attracted great attention due to their remarkable proper- ties such as extremely high quality factor, small mode volume, tight confinement of modes, and strong evanescent field. All these properties of WGM microresonators have ensured their great potentials for applications, such as physical sen- sors, bio/chemical sensors and microlasers. In this mini-review, the key parameters and coupling conditions of WGM microresonators are firstly introduced. The geometries of WGM optical microcavities are presented based on their fabri- cation methods. This is followed by the discussion on the state-of-the-art applications of WGM microresonators in sen- sors and microlasers.
基金supported by the National Natural Science Foundation of China(No.52175095)the Young Top-Notch Talent Cultivation Program of Hubei Province of China。
文摘The design of thermoelastic damping(TED)affected by the phase-lagging non-Fourier heat conduction effects becomes significant but challenging for enlarging the quality factor of widely-used microresonators operating in extreme situations,including ultra-high excitation frequency and ultra-low working temperature.However,there does not exist a rational method for designing the TED in the framework of non-Fourier heat conduction law.This work,therefore,proposes a design framework to achieve low thermoelastic dissipation of microresonators governed by the phase-lagging heat conduction law.The equation of motion and the heat conduction equation for phase-lagging TED microresonators are derived first,and then the non-Fourier TED design problem is proposed.A topology optimization-based rational design method is used to resolve the design problem.What is more,a two-dimensional(2D)plain-strain-based finite element method(FEM)is developed as a solver for the topology optimization process.Based on the suggested rational design technique,numerical instances with various phase lags are investigated.The results show that the proposed design method can remarkably reduce the dissipation of microresonators by tailoring their substructures.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFA0301802)the National Natural Science Foundation of China(Grant Nos.61521001 and 11890704)the Key R&D Program of Guangdong Province,China(Grant No.2018B030326001).
文摘In superconducting circuit,microwave resonators and capacitors are crucial components,and their quality has a strong impact on circuit performance.Here we develop a novel wet etching process to define these two components using common photoresist developer as etchant.This method reduces subsequent steps and can be completed immediately after development.By measuring the internal quality factor of resonators,we show that it is possible to achieve similar or better performance when compared with samples made by standard etching processes.This easy-to-implement method may boost the yield hence providing an alternative fabrication process for microwave resonators and capacitors.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12365003, 12364024, and 11864014)the Natural Science Foundation of Jiangxi Province, China (Grant Nos. 20212BAB201014 and 20224BAB201023)。
文摘We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emitter. Quantum routing probability in the output port is obtained via the real-space Hamiltonian. By adjusting the resonator–emitter coupling and the drive, the desired continuous central frequencies for the resonance peaks of routing photons can be manipulated nearly linearly, with the assistance of Rabi splitting effect and optical Stark shift. The proposed routing system may provide potential applications in designing other frequency-modulation quantum optical devices, such as multiplexers,filters, and so on.
基金Key Project Foundation from Depart ment of Education of Hubei Province(D200512011)
文摘The ring microresonator filter considering resonator inner loss is analyzed theoretically, which has one input port and two output ports. Some universal relations for coupling of optical power between microresonator and dielectric waveguides are presented. The analytical expressions of filter bandwidth or the full width at half maximum(FWHM), free spectral range and finesse of resonator are derived. The characteristics of the ring microresonator filter are discussed numerically. It is demonstrated that the loss of the ring resonator reduces the peak value of transmission, widens the filter bandwidth, and reduces the finesse of the resonator filter.
文摘A 4.13 MHz reference oscillator incorporating a capacitive single-crystal-silicon （SCS） micromechanical resonator is presented. The microresonator is fabricated using a cavity silicon-on-insulator （cavity-SOl） process and is excited in the Lain6 mode with electrostatic driving and capacitive sensing. The Lam6 mode may be described as a square plate that is cont- racting along one axis in the fabrication plane, while simultaneously extending along an orthogonal axis in the same plane. The microresonator exhibits a quality factor as high as 1.4 × 10^6 and a resonant frequency of 4.13 MHz at a pressure of 0.08 mbar. The output spectrum of the oscillator shows that the silicon micromechanical resonator is adapted as a timing element for a precision oscillator.
基金National Natural Science Foundation of China(No.50135040)Science Foundation of Shanghai Municipality Education Commission through the Key Discipline Program(No.970104).
文摘To improve the performance and reliability of microelectromechanical system＇s devices, it is necessary to understand the effect of friction which exists in the majority of microelectromechanical systems （MEMS） with a large ratio of surface area to their volume. The model of electrostatic tangential force of the shuttle in laterally driven comb microresonator is established based on the rule of energy conservation. The effects of microscale, surface roughness, applied voltage, and micro asperities or dents or holes formed in fabrication are investigated, and the electrostatic resistance between two charged moving plates is analyzed. The analytic results are coincident well with those of ANSYS simulation. It is found that the electrostatic resistance becomes high as the increase of the ratio of the shuttle width to the gap between moving plates and the relative surface roughness or the increment of the applied voltage.
文摘We have suggested a novel multiport quantum router of single photons with reflection feedback, which is formed by three waveguides coupled with four single-mode microresonators. The single-photon routing probabilities of four channels in the coupled system are studied theoretically by applying the real-space approach. Numerical results indicate that unidirectional routing in these output channels can be effectively implemented, and the router is tunable to route desired frequencies into the output ports, by varying the inter-resonator detunings via spinning resonator technology. Therefore, the proposed multichannel system can provide potential applications in optical quantum communication.
基金European Research Council(756966)MaxPlanck-Gesellschaft+1 种基金H2020 Marie Sklodowska-Curie COFUND“Multiply”(713694)Marie Curie Innovative Training Network“Microcombs”(812818)。
文摘Microresonator dispersion plays a crucial role in shaping the nonlinear dynamics of microcavity solitons.Here,we introduce and validate a method for dispersion engineering through modulating a portion of the inner edge of ring waveguides.We demonstrate that such partial modulation has a broadband effect on the dispersion profile,whereas modulation on the entire resonator's inner circumference leads to mode splitting primarily affecting one optical mode.The impact of spatial modulation amplitude,period,and number of modulations on the mode splitting profile is also investigated.Through the integration of four modulated sections with different modulation amplitudes and periods,we achieve mode splitting across more than 50 modes over a spectral range exceeding 100 nm in silicon nitride resonators.These results highlight both the simplicity and efficacy of our method in achieving flatter dispersion profiles.
基金National Key Research and Development Program of China (2023YFB3906401, 2021YFA1400803)National Natural Science Foundation of China (12341403,12293054, 92463304, 12341402)+2 种基金Fundamental Research Funds for the Central Universities (021314380260)Zhangjiang LaboratoryNatural Science Foundation of Jiangsu Province (BK20221440)。
文摘Chip-based optical microresonators with ultra-high Q-factors are becoming increasingly important to a variety of applications. However, the losses of on-chip microresonators with the highest Q-factor reported in the past are still far from their material absorption limits. Here, we demonstrate an on-chip silica microresonator that has approached the absorption limit of the state-of-the-art material on chip, realizing, to our knowledge, record intrinsic Q-factors exceeding 3 billion at both 1560 nm and 1064 nm. This fact is corroborated by photo-thermal spectroscopy measurements. Especially, compared with the standard optical fibers, its corresponding optical losses are only 38.4 times and 7.7 times higher at the wavelengths of 1560 nm and 1064 nm, respectively.To exhibit the performance of such fabricated microresonator, we achieve a record-low optical parametric oscillation threshold(31.9 μW) for millimeter-sized microresonators and generate a single-soliton microcomb with a record-low pump power of 220.2 μW for all soliton microcombs realized thus far.
基金Max-Planck-GesellschaftH2020 European Research Council(756966)The Chinese University of Hong Kong,Shenzhen(UDF01003527)。
文摘With the rapid development of the Internet of Things and big data,integrated optical switches are gaining prominence for applications in on-chip optical computing,optical memories,and optical communications.Here,we propose a novel approach for on-chip optical switches by utilizing the nonlinear optical Kerr effect induced spontaneous symmetry breaking(SSB),which leads to two distinct states of counterpropagating light in ring resonators.This technique is based on our first experimental observation of on-chip symmetry breaking in a high-Q(9.4×10~6)silicon nitride resonator with a measured SSB threshold power of approximately 3.9 mW.We further explore the influence of varying pump powers and frequency detunings on the performance of SSB-induced optical switches.Our work provides insights into the development of new types of photonic data processing devices and provides an innovative approach for the future implementation of on-chip optical memories.
基金supported by the National Key Basic Research Program of China(Grant No.2014CB921300)the National Natural Science Foundation of China(Grant Nos.61275205,11174305 and 61205209)the Fundamental Research Funds for the Central Universities
文摘We report on second harmonic generation(SHG) in on-chip high-Q(>105) lithium niobate(Li Nb O3, LN) microresonators fabricated by femtosecond laser micromachining. We examine the efficiency of SHG with either a continuous-wave(CW) or an ultrashort pulsed pump laser. The normalized conversion efficiencies of SHG obtained with the CW and pulsed pump lasers are measured to be 1.35×10?5 m W?1 and 2.30×10?6 m W?1, respectively.
基金The results presented in Sections 2.5 and 3.2 were obtained with the support of the Russian Science Foundation(project 22-22-00872)The results presented in Sections 2.3,3.4 and 4 were obtained with the support of the Russian Science Foundation(Project 20-12-00344)+5 种基金Y.-H.L.acknowledges support from the China Postdoctoral Science Foundation(Grant No.2022M721482)W.L.acknowledges support from the National Natural Science Foundation of China(Grant No.62075233)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-69)J.L.acknowledges support from the National Natural Science Foundation of China(Grant No.12261131503)Shenzhen−Hong Kong Cooperation Zone for Technology and Innovation(HZQB-KCZYB2020050)from the Guangdong Provincial Key Laboratory(2019B121203002).
文摘The stabilization and manipulation of laser frequency by means of an external cavity are nearly ubiquitously used in fundamental research and laser applications. While most of the laser light transmits through the cavity, in the presence of some back-scattered light from the cavity to the laser, the self-injection locking effect can take place, which locks the laser emission frequency to the cavity mode of similar frequency. The self-injection locking leads to dramatic reduction of laser linewidth and noise. Using this approach, a common semiconductor laser locked to an ultrahigh-Q microresonator can obtain sub-Hertz linewidth, on par with state-of-the-art fiber lasers. Therefore it paves the way to manufacture high-performance semiconductor lasers with reduced footprint and cost. Moreover, with high laser power, the optical nonlinearity of the microresonator drastically changes the laser dynamics, offering routes for simultaneous pulse and frequency comb generation in the same microresonator. Particularly, integrated photonics technology, enabling components fabricated via semiconductor CMOS process, has brought increasing and extending interest to laser manufacturing using this method. In this article, we present a comprehensive tutorial on analytical and numerical methods of laser self-injection locking, as well a review of most recent theoretical and experimental achievements.
基金supported by the National Natural Science Foundation of China(11674230)973 Program(2015CB352001)National Natural Science Foundation of China(11434005).
文摘Single-mode lasing in whispering-gallery mode(WGM)microresonators is challenging to achieve.In bottle microresonators,the highly non-degenerated WGMs are spatially well-separated along the long-axis direction and provide mode-selection capability.In this work,by engineering the pump intensity to modify the spatial gain profiles of bottle microresonators,we demonstrate a simple and general approach to realizing single-mode WGM lasing in polymer bottle microresonators.The pump intensity is engineered into an interference distribution on the bottle microresonator surface.By tuning the spacing between axial positions of the interference pump patterns,the mode intensity profiles of single-bottle WGMs can be spatially overlapped with the interference stripes,intrinsically enabling single-mode lasing and selection.Attractive advantages of the system,including high sidemode suppression factors 420 dB,large spectral tunability 48 nm,low-lasing threshold and reversible control,are presented.Our demonstrated approach may have a variety of promising applications,ranging from tunable single-mode lasing and sensing to nonlinear optics.
基金supported by the National Key R&D Program of China(Grant Nos.2016YFA0301302,and 2016YFA0301700)National Natural Science Foundation of China(Grant Nos.11825402,61590932,11774333,62061160487,12004373,11734009,and 11874375)+4 种基金Anhui Initiative in Quantum Information Technologies(Grant No.AHY130300)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB24030601)Beijing Academy of Quantum Information Sciences(Grant No.Y18G20)Fundamental Research Funds for the Central Universitiespartially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘On-chip bright quantum sources with multiplexing ability are extremely high in demand for integrated quantum networks with unprecedented scalability and complexity.Here,we demonstrate a bright and broadband biphoton quantum source with spectral multiplexing generated in a lithium niobate microresonator system.Without introducing the conventional domain poling,the on-chip microdisk produces photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion.Experimentally,the multiplexed photon pairs are characterized by 30 nm bandwidth limited by the filtering system,providing over 40 multiplexing channels with a 0.8 nm channel spacing.Meanwhile,the generation rate reaches 5.13 MHz/μW with a coincidence-to-accidental ratio up to 804,and the quantum source manifests a high purity with a heralded single photon correlation g^((2))_(H)(0)=0.0098±0.0021.Furthermore,the energy-time entanglement is demonstrated with an excellent interference visibility of 96.5%±2%.Such a quantum source at the telecommunication band paves the way for high-dimensional entanglement and future integrated quantum information systems.
基金This work was supported by the National Key Research and Development Program of China(No.2020YFB2205801)National Natural Science Foundation of China(Nos.11934012,11874342,and 92050109)the Fundamental Research Funds for the Central Universities.C.H.Dong was also supported by the State Key Laboratory of Advanced Optical Communication Systems and Networks,Shanghai Jiao Tong University,China.This work was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.The authors declare no conflicts of interest.
文摘The microresonator-based soliton microcomb has shown a promising future in many applications.In this work,we report the fabrication of high quality[Q]Si_(3)N_(4)microring resonators for soliton microcomb generation.By developing the fabri-cation process with crack isolation trenches and annealing,we can deposit thick stoichiometric Si3N4 film of 800 nm without cracks in the central area.The highest intrinsic Q of the Si_(3)N_(4)microring obtained in our experiments is about 6×10^(6),corresponding to a propagation loss as low as 0.058 dBm/cm.With such a high Q film,we fabricate microrings with the anomalous dispersion and demonstrate the generation of soliton microcombs with 100 mW on-chip pump power,with an optical parametric oscillation threshold of only 13.4 mW.Our Si_(3)N_(4)integrated chip provides an ideal platform for researches and applications of nonlinear photonics and integrated photonics.
基金supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB01030200)the National Basic Research Program of China(Grant Nos.2011CB921200 and2011CBA00200)+2 种基金the National Natural Science Foundation of China(Grant No.61308079)Anhui Provincial Natural Science Foundation(Grant No1508085QA08)the Fundamental Research Funds for the Central Universities
文摘We have reported the high-Q whispering gallery modes(WGMs) in a polydimethylsiloxane(PDMS) optical microresonators with broad tuning range. The PDMS microresonators are fabricated at the center of two collimating fiber tips, which can be controlled by the piezoelectric stage. Through stretching the fiber stem, the tuning range of WGMs are demonstrated more than 50 nm.Further investigations demonstrated that the WGM shift has a high force sensitivity(～ 19.7 pm/μN) of the gravitation when the microcavity is stretched by a weight. The theoretical analysis reveals that the high force sensitivity of polymer microresonator can be used for the weak force or height measurement.
基金the National Key Research and Development Program of China(No.2021YFB2800604)the National Natural Science Foundation of China(Grant Nos.91850115 and 11774110)the State Key Laboratory of Applied Optics(No.SKLAO2021001A10).
文摘Second-order(χ^((2))) optical nonlinearity is one of the most common mechanisms for modulating and generating coherent light in photonic devices.Due to strong photon confnement and long photon lifetime,integrated microresonators have emerged as an ideal platform for investigation of nonlinear optical efects.However,existing silicon-based materials lack a χ^((2)) response due to their centrosymmetric structures.A variety of novel material platforms possessing χ^((2)) nonlinearity have been developed over the past two decades.This review comprehensively summarizes the progress of second-order nonlinear optical efects in integrated microresonators.First,the basic principles of χ^((2)) nonlinear efects are introduced.Afterward,we highlight the commonly used χ^((2)) nonlinear optical materials,including their material properties and respective functional devices.We also discuss the prospects and challenges of utilizing χ^((2)) nonlinearity in the feld of integrated microcavity photonics.
基金This work was supported in part by the Air Force Office of Scientific Research under grant FA9550-15-1-0211, from the DARPA PULSE program through grant W31P40-13-1-0018 from AMR- DEC, and from the National Science Foundation under grant ECCS- 1509578.
文摘Microresonator frequency combs （microcombs） are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the study of microcombs to reveal and control the comb formation dynamics. In this paper, we reviewed the microwave photonic techniques and applications that are connected with microcombs. The future research directions of microcomb-based microwave photonics were also discussed.
基金funded by the National Key R&D Program of China(No.2019YFA0705000)the National Natural Science Foundation of China(Nos.12004116,11874154,and 11734009)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB16030300)the Shanghai Municipal Science and Technology Major Project(No.2019SHZDZX01)the Natural Science and Engineering Research Council of Canada(NSERC)Discovery(No.RGPIN-2020-05938)。
文摘We demonstrate high-quality(intrinsic Q factor∼2.8×106)racetrack microresonators fabricated on lithium niobate thin film with a free spectral range(FSR)of∼86 pm.By integrating microelectrodes alongside the two straight arms of the racetrack resonator,the resonance wavelength around 1550 nm can be red shifted by 92 pm when the electric voltage is raised from−100 V to 100 V.The microresonators with the tuning range spanning over a full FSR are fabricated using photolithography assisted chemo-mechanical etching.
