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
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
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
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
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
Since their inception, frequency combs generated in microresonators, known as microcombs, have sparked significant scientific interests. Among the various applications leveraging microcombs, soliton microcombs are oft...Since their inception, frequency combs generated in microresonators, known as microcombs, have sparked significant scientific interests. Among the various applications leveraging microcombs, soliton microcombs are often preferred due to their inherent mode-locking capability. However, this choice introduces additional system complexity because an initialization process is required. Meanwhile, despite the theoretical understanding of the dynamics of other comb states, their practical potential, particularly in applications like sensing where simplicity is valued, remains largely untapped. Here, we demonstrate controllable generation of sub-combs that bypasses the need for accessing bistable regime. And in a graphene-sensitized microresonator, the sub-comb heterodynes produce stable, accurate microwave signals for high-precision gas detection. By exploring the formation dynamics of sub-combs, we achieved 2 MHz harmonic comb-to-comb beat notes with a signal-to-noise ratio (SNR) greater than 50 dB and phase noise as low as – 82 dBc/Hz at 1 MHz offset. The graphene sensitization on the intracavity probes results in exceptional frequency responsiveness to the adsorption of gas molecules on the graphene of microcavity surface, enabling detect limits down to the parts per billion (ppb) level. This synergy between graphene and sub-comb formation dynamics in a microcavity structure showcases the feasibility of utilizing microcombs in an incoherent state prior to soliton locking. It may mark a significant step toward the development of easy-to-operate, systemically simple, compact, and high-performance photonic sensors.展开更多
Soliton generation schemes have attracted considerable scholarly attention.This paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons(DKSs).Reversible soliton gener...Soliton generation schemes have attracted considerable scholarly attention.This paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons(DKSs).Reversible soliton generation relies on the thermal stabilization of the auxiliary laser,coupled with backward tuning of the pump laser,significantly increasing the range of soliton steps by over 10 times.Moreover,the method alleviates the stringent auxiliary laser detuning requirement.By adjusting the detuning of the auxiliary laser,diverse numbers of solitons can be deterministically generated,enhancing both flexibility and precision.展开更多
In this paper,we experimentally investigate the tuning characteristics of laser modes for an ultrahigh-Q Er^(3+)-doped microbottle resonator(MBR)based on the whispering gallery mode(WGM).Thanks to the optimized Er^(3+...In this paper,we experimentally investigate the tuning characteristics of laser modes for an ultrahigh-Q Er^(3+)-doped microbottle resonator(MBR)based on the whispering gallery mode(WGM).Thanks to the optimized Er^(3+)doping technique,the laser threshold could be as low as 70μW.Benefiting from the abundant axial modes and radial modes of the MBR,our experiments demonstrate that the number of laser modes can be flexibly controlled by varying the pump power,adjusting the coupling positions along the axis of the MBR,as well as modifying the coupling diameter of the tapered fiber.The laser mode switching is performed from single-mode to multimodes.Furthermore,different from the traditional external tuning method,we propose a simple and stable approach for continuous wavelength tuning of the laser mode based on the thermal effect associated with the high Q MBR.By precisely adjusting the pump laser wavelength,the emitted laser wavelength can be tuned over a range of 0.102 nm with a high linearity of 99.96%.The engineering of laser mode switching and precise wavelength tuning of the Er^(3+)-doped MBR is expected to have promising applications in miniature tunable single-mode lasers,laser precision measurement,and so on.展开更多
Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas ...Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas electrochemical meters,although more accurate,are fragile,prone to drift,and unsuitable for small volumes.In this paper,we propose a method for the optical detection of pH based on a multiplexed sensor with 4D microcavities fabricated via two-photon polymerization.This approach employs pH-triggered reversible variations in microresonator geometry and integrates hundreds of dual optically coupled 4D microcavities to achieve the detection limit of 0.003 pH units.The proposed solution is a clear example of the use-case-oriented application of two-photon polymerized structures of high optical quality.Owing to the benefits of the multiplexed imaging platform,the dual 4D microresonators can be integrated with other microresonator types for pH-corrected biochemical studies.展开更多
The rapid development of optical frequency combs from their table-top origins towards chip-scale platforms has opened up exciting possibilities for comb functionalities outside laboratories.Enhanced nonlinear processe...The rapid development of optical frequency combs from their table-top origins towards chip-scale platforms has opened up exciting possibilities for comb functionalities outside laboratories.Enhanced nonlinear processes in microresonators have emerged as a mainstream comb-generating mechanism with compelling advantages in size,weight,and power consumption.The established understanding of gain and loss in nonlinear microresonators,along with recently developed ultralow-loss nonlinear photonic circuitry,has boosted the optical energy conversion efficiency of microresonator frequency comb(microcomb)devices from below a few percent to above 50%.This review summarizes the latest advances in novel photonic devices and pumping strategies that contribute to these milestones of microcomb efficiency.The resulting benefits for high-performance integration of comb applications are also discussed before summarizing the remaining challenges.展开更多
Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and a...Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.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
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
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
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.
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.
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support from the National Key Research and Development Program of China(Nos.2023YFB2805600,2021YFB2800602,2023YFB2806200)the National Natural Science Foundation of China(Grant Nos.U2130106 and 62305050)+1 种基金the National Postdoctoral Innovation Talent Support Program of China(No.BX20220056)Industrial Key Project of China Southern Power Grid(No.CG2100022001608777).
文摘Since their inception, frequency combs generated in microresonators, known as microcombs, have sparked significant scientific interests. Among the various applications leveraging microcombs, soliton microcombs are often preferred due to their inherent mode-locking capability. However, this choice introduces additional system complexity because an initialization process is required. Meanwhile, despite the theoretical understanding of the dynamics of other comb states, their practical potential, particularly in applications like sensing where simplicity is valued, remains largely untapped. Here, we demonstrate controllable generation of sub-combs that bypasses the need for accessing bistable regime. And in a graphene-sensitized microresonator, the sub-comb heterodynes produce stable, accurate microwave signals for high-precision gas detection. By exploring the formation dynamics of sub-combs, we achieved 2 MHz harmonic comb-to-comb beat notes with a signal-to-noise ratio (SNR) greater than 50 dB and phase noise as low as – 82 dBc/Hz at 1 MHz offset. The graphene sensitization on the intracavity probes results in exceptional frequency responsiveness to the adsorption of gas molecules on the graphene of microcavity surface, enabling detect limits down to the parts per billion (ppb) level. This synergy between graphene and sub-comb formation dynamics in a microcavity structure showcases the feasibility of utilizing microcombs in an incoherent state prior to soliton locking. It may mark a significant step toward the development of easy-to-operate, systemically simple, compact, and high-performance photonic sensors.
基金supported by the National Key Research and Development Program of China(No.2020YFB2010701)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY223154).
文摘Soliton generation schemes have attracted considerable scholarly attention.This paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons(DKSs).Reversible soliton generation relies on the thermal stabilization of the auxiliary laser,coupled with backward tuning of the pump laser,significantly increasing the range of soliton steps by over 10 times.Moreover,the method alleviates the stringent auxiliary laser detuning requirement.By adjusting the detuning of the auxiliary laser,diverse numbers of solitons can be deterministically generated,enhancing both flexibility and precision.
基金supported by the National Natural Science Foundation of China(Nos.62205001 and 62275001)。
文摘In this paper,we experimentally investigate the tuning characteristics of laser modes for an ultrahigh-Q Er^(3+)-doped microbottle resonator(MBR)based on the whispering gallery mode(WGM).Thanks to the optimized Er^(3+)doping technique,the laser threshold could be as low as 70μW.Benefiting from the abundant axial modes and radial modes of the MBR,our experiments demonstrate that the number of laser modes can be flexibly controlled by varying the pump power,adjusting the coupling positions along the axis of the MBR,as well as modifying the coupling diameter of the tapered fiber.The laser mode switching is performed from single-mode to multimodes.Furthermore,different from the traditional external tuning method,we propose a simple and stable approach for continuous wavelength tuning of the laser mode based on the thermal effect associated with the high Q MBR.By precisely adjusting the pump laser wavelength,the emitted laser wavelength can be tuned over a range of 0.102 nm with a high linearity of 99.96%.The engineering of laser mode switching and precise wavelength tuning of the Er^(3+)-doped MBR is expected to have promising applications in miniature tunable single-mode lasers,laser precision measurement,and so on.
基金the German Federal Ministry for Research and Education(BMBF)for partially funding this work under the VIP+-Programme in the project IntellOSS,03VP08220.
文摘Water monitoring,environmental analysis,cell culture stability,and biomedical applications require precise pH control.Traditional methods,such as pH strips and meters,have limitations:pH strips lack precision,whereas electrochemical meters,although more accurate,are fragile,prone to drift,and unsuitable for small volumes.In this paper,we propose a method for the optical detection of pH based on a multiplexed sensor with 4D microcavities fabricated via two-photon polymerization.This approach employs pH-triggered reversible variations in microresonator geometry and integrates hundreds of dual optically coupled 4D microcavities to achieve the detection limit of 0.003 pH units.The proposed solution is a clear example of the use-case-oriented application of two-photon polymerized structures of high optical quality.Owing to the benefits of the multiplexed imaging platform,the dual 4D microresonators can be integrated with other microresonator types for pH-corrected biochemical studies.
基金supported by Beijing Natural Science Foundation(Z210004)National Natural Science Foundation of China(92150108)+2 种基金supported by European Research Council(CoG GA 771410)Swedish Research Council(project 2020-00453)Knut and Alice Wallenberg Foundation(KAW 2018.0090).
文摘The rapid development of optical frequency combs from their table-top origins towards chip-scale platforms has opened up exciting possibilities for comb functionalities outside laboratories.Enhanced nonlinear processes in microresonators have emerged as a mainstream comb-generating mechanism with compelling advantages in size,weight,and power consumption.The established understanding of gain and loss in nonlinear microresonators,along with recently developed ultralow-loss nonlinear photonic circuitry,has boosted the optical energy conversion efficiency of microresonator frequency comb(microcomb)devices from below a few percent to above 50%.This review summarizes the latest advances in novel photonic devices and pumping strategies that contribute to these milestones of microcomb efficiency.The resulting benefits for high-performance integration of comb applications are also discussed before summarizing the remaining challenges.
基金support from the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation(Grant Nos.1824568,1810506,1741707,and 1829071)the Office of Naval Research(Grant No.N00014-16-1-2094).
文摘Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.
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.
