Large-signal modulation capability, as an important performance indicator, is directly related to the high-speed optical communication technology involved. We experimentally and theoretically investigate the large-sig...Large-signal modulation capability, as an important performance indicator, is directly related to the high-speed optical communication technology involved. We experimentally and theoretically investigate the large-signal modulation characteristics of the simultaneous ground-state （GS） and the excited-state （ES） lasing in InAs/OaAs quantum dot laser diodes. The large-signal modulation capability of total light intensity in the transition regime from OS lasing to two-state lasing is unchanged as the bias-current increases. However, GS and ES large-signal eye diagrams show obvious variations during the transition. Relaxation oscillations and large-signal eye diagrams for OS, ES, and total light intensities are numerically simulated and analyzed in detail by using a rate-equation model. The -ndings show that a complementary relationship between the light intensities for OS and ES lasing exists in both the transition regime and the two-state lasing regime, leading to a much smaller overshooting power and a shorter settling time for the total light intensity. Therefore, the eye diagrams of GS or ES lasing are diffuse whereas those of total light intensity are constant as the bias-current increases in the transition regime.展开更多
We report on a study of terahertz(THz) generation using implanted In Ga As photomixers and multi-wavelength quantum dot lasers. We carry out In Ga As materials growth, optical characterization, device design and fabri...We report on a study of terahertz(THz) generation using implanted In Ga As photomixers and multi-wavelength quantum dot lasers. We carry out In Ga As materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime, we employ proton implantation into an epitaxial layer of lattice matched In Ga As grown on InP. Under a 1.55 μm multimode In GaAs/In GaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.展开更多
Quantum dot lasers have excellent characteristics such as temperature stability of threshold current and ultra-high material gain. Quantum dot structures fabricated by self-organized growth have high crystalline perfe...Quantum dot lasers have excellent characteristics such as temperature stability of threshold current and ultra-high material gain. Quantum dot structures fabricated by self-organized growth have high crystalline perfection, high quantum yield of radiative recombination and high size homogeneity. Main advantages and operating properties of quantum dot lasers fabricated by self-organized growth are briefly introduced.展开更多
Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked...Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.展开更多
Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold...Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold current density in a wide temperature range are analyzed and the negative characteristic temperature and oscillatory characteristic temperature appearing in that temperature range are discussed. Also,the improvement of quantum dot lasers＇ performance is investigated through vertical stacking and p-type doping and the optimal dot density, which corresponds to minimal threshold current density,is calculated.展开更多
We review recent advances in the field of quantum dot lasers on silicon. A summary of device performance,reliability, and comparison with similar quantum well lasers grown on silicon will be presented. We consider the...We review recent advances in the field of quantum dot lasers on silicon. A summary of device performance,reliability, and comparison with similar quantum well lasers grown on silicon will be presented. We consider the possibility of scalable, low size, weight, and power nanolasers grown on silicon enabled by quantum dot active regions for future short-reach silicon photonics interconnects.展开更多
Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent pr...Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.展开更多
Based on three-level exciton model,the enhanced photonic microwave signal generation by using a sole excited-state(ES)emitting quantum dot(QD)laser under both optical injection and optical feedback is numerically stud...Based on three-level exciton model,the enhanced photonic microwave signal generation by using a sole excited-state(ES)emitting quantum dot(QD)laser under both optical injection and optical feedback is numerically studied.Within the range of period-one(P1)dynamics caused by the optical injection,the variations of microwave frequency and microwave intensity with the parameters of frequency detuning and injection strength are demonstrated.It is found that the microwave frequency can be continuously tuned by adjusting the injection parameters,and the microwave intensity can be enhanced by changing the injection strength.Moreover,considering that the generated microwave has a wide linewidth,an optical feedback loop is further employed to compress the linewidth,and the effect of feedback parameters on the linewidth is investigated.It is found that with the increase of feedback strength or delay time,the linewidth is evidently decreased due to the locking effect.However,for the relatively large feedback strength or delay time,the linewidth compression effect becomes worse due to the gradually destroyed P1 dynamics.Besides,through optimizing the feedback parameters,the linewidth can be reduced by up to more than one order of magnitude for different microwave frequencies.展开更多
A low phase noise millimeter-wave(MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Pérot(F-P) quantum dot mode-locked laser. A novel method is proposed to generate l...A low phase noise millimeter-wave(MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Pérot(F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven Li Nb O3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is-112 d Bc/Hz and-106 d Bc/Hz at an offset of 1 k Hz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.展开更多
In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer functio...In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.展开更多
Global data traffic is growing rapidly,and the demand for optoelectronic transceivers applied in data centers(DCs)is also increasing correspondingly.In this review,we first briefly introduce the development of optoele...Global data traffic is growing rapidly,and the demand for optoelectronic transceivers applied in data centers(DCs)is also increasing correspondingly.In this review,we first briefly introduce the development of optoelectronics transceivers in DCs,as well as the advantages of silicon photonic chips fabricated by complementary metal oxide semiconductor process.We also summarize the research on the main components in silicon photonic transceivers.In particular,quantum dot lasers have shown great potential as light sources for silicon photonic integration—whether to adopt bonding method or monolithic integration—thanks to their unique advantages over the conventional quantum-well counterparts.Some of the solutions for highspeed optical interconnection in DCs are then discussed.Among them,wavelength division multiplexing and four-level pulseamplitude modulation have been widely studied and applied.At present,the application of coherent optical communication technology has moved from the backbone network,to the metro network,and then to DCs.展开更多
We investigate InAs/GaAs quantum dot （QD） lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of...We investigate InAs/GaAs quantum dot （QD） lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of InAs dot layers are set as 425 and 500℃, respectively. Ridge waveguide laser diodes are fabricated, and the characteristics of the QD lasers are systematically studied. The laser diodes with QDs grown at 425 ~C show better performance, such as threshold current density, output power, internal quantum efficiency, and characteristic temperature, than those with QDs grown at 500℃. This finding is ascribed to the higher QD density and more uniform size distribution of QDs achieved at 425℃.展开更多
Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be...Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.展开更多
We report on a quantum dot quantum cascade detector（QD-QCD）, whose structure is derived from a QD cascade laser. In this structure, more ordered In As QD layers formed in the Stranski-Krastanow growth mode on a thin...We report on a quantum dot quantum cascade detector（QD-QCD）, whose structure is derived from a QD cascade laser. In this structure, more ordered In As QD layers formed in the Stranski-Krastanow growth mode on a thin Ga As buffer layer are incorporated into the active region. This QD-QCD can operate up to room temperature with a peak detection wavelength of 5.8 μm. A responsivity of 3.1 mA/W at 160 K and a detectivity of 3.6 × 10~8 Jones at 77 K are obtained. The initial performance of the detector is promising, and, by further optimizing the growth of InA s QDs, integrated QD-quantum cascade laser/QCD applications are expected.展开更多
Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contem...Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contemporary communication systems,radar,sensing,and signal processing.Driving the rapid advancement of MWP are pivotal technologies such as optical frequency combs,photonic integrated circuits,and advanced modulation formats.The integration of photonic integrated circuit technology with hybrid integration techniques holds the promise of realizing MWP systems on a single chip,while comb shaping technology endows MWP systems with programmable and reconfigurable capabilities.In this paper,we present a review of our recent research,which focused on exploring the full spectrum of potential applications for quantum dash lasers in MWP systems.Leveraging principles of finite impulse response filters,our MWP system not only facilitates conventional filtering but also enables instantaneous frequency measurement and waveform generation.A distinguishing feature of MWP filters is their uniform delay.After converting it into a uniform phase difference,it underpins the development of MWP-based phase antenna array systems.Furthermore,this uniform delay finds application in time-interleaved photonic analog-to-digital conversion.展开更多
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0402302the National Natural Science Foundation of China under Grant No 91433206
文摘Large-signal modulation capability, as an important performance indicator, is directly related to the high-speed optical communication technology involved. We experimentally and theoretically investigate the large-signal modulation characteristics of the simultaneous ground-state （GS） and the excited-state （ES） lasing in InAs/OaAs quantum dot laser diodes. The large-signal modulation capability of total light intensity in the transition regime from OS lasing to two-state lasing is unchanged as the bias-current increases. However, GS and ES large-signal eye diagrams show obvious variations during the transition. Relaxation oscillations and large-signal eye diagrams for OS, ES, and total light intensities are numerically simulated and analyzed in detail by using a rate-equation model. The -ndings show that a complementary relationship between the light intensities for OS and ES lasing exists in both the transition regime and the two-state lasing regime, leading to a much smaller overshooting power and a shorter settling time for the total light intensity. Therefore, the eye diagrams of GS or ES lasing are diffuse whereas those of total light intensity are constant as the bias-current increases in the transition regime.
基金supported in part by NSERC. HCL thanks the support by the National Ma jor Basic Research Pro jects (2011CB925603)Shanghai Municipal Ma jor Basic Research Pro ject (09DJ1400102)
文摘We report on a study of terahertz(THz) generation using implanted In Ga As photomixers and multi-wavelength quantum dot lasers. We carry out In Ga As materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime, we employ proton implantation into an epitaxial layer of lattice matched In Ga As grown on InP. Under a 1.55 μm multimode In GaAs/In GaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.
文摘Quantum dot lasers have excellent characteristics such as temperature stability of threshold current and ultra-high material gain. Quantum dot structures fabricated by self-organized growth have high crystalline perfection, high quantum yield of radiative recombination and high size homogeneity. Main advantages and operating properties of quantum dot lasers fabricated by self-organized growth are briefly introduced.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2803600)the National Natural Science Foundation of China(Grant Nos.62204072,62334013,and U22A2093)+3 种基金the Basic and Applied Basic Research Foundation of Guangdong Province(Grant Nos.2021A1515110076 and 2023A1515012304)the Shenzhen Science and Technology Innovation Program(Grant Nos.GXWD20220811163623002,RCBS20210609103824050,JCYJ20240813104819027,and KJZD20240903101100002)the Research Fund of the National Key Laboratory of Laser Spatial Information(Grant No.LSI2025WDZC03)the Open Research Program of the State Key Laboratory of Radio Frequency Heterogeneous Integration(Grant No.KF2025010).
文摘Optical frequency combs(OFCs)are highly promising candidates as multichannel light sources for photonic integrated circuits(PICs).We present a tunable on-chip OFC source based on quantum dot collidingpulse mode-locked lasers(QD-CPMLs),capable of generating both amplitude-modulated(AM)and frequencymodulated(FM)combs through external-cavity locking.A free-running fourth-order QD-CPML with a 100 GHz repetition rate is demonstrated to produce FM and AM combs under different bias conditions,achieving an ultra-wide comb with a 3-dB bandwidth of 1.8 THz and a 10-dB bandwidth of 2.5 THz.By leveraging externalcavity locking,the modulation dynamics of the comb are finely tuned,significantly expanding the AM comb range while reducing pulse width and chirp.The shortest pulse width achieved is 0.6 ps,with a minimum time-bandwidth product of 0.33,approaching the transform limit for hyperbolic secant pulses.The near-zero linewidth enhancement factor of the QD-CPML effectively suppresses coherence collapse under optical feedback,whereas its low group velocity dispersion facilitates the generation of narrow pulses and broad bandwidths.The ability to dynamically control AM and FM comb regions through external-cavity locking represents an innovative strategy for tunable OFC generation,offering potential for applications in sensing,spectroscopy,and optical communications within PICs.
文摘Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold current density in a wide temperature range are analyzed and the negative characteristic temperature and oscillatory characteristic temperature appearing in that temperature range are discussed. Also,the improvement of quantum dot lasers＇ performance is investigated through vertical stacking and p-type doping and the optimal dot density, which corresponds to minimal threshold current density,is calculated.
基金supported by DARPA MTO E-PHI and the Semiconductor Research Corporationsupport of NSF graduate research fellowships
文摘We review recent advances in the field of quantum dot lasers on silicon. A summary of device performance,reliability, and comparison with similar quantum well lasers grown on silicon will be presented. We consider the possibility of scalable, low size, weight, and power nanolasers grown on silicon enabled by quantum dot active regions for future short-reach silicon photonics interconnects.
基金the Defense Advanced Research Projects Agency of the United States under Grant No.W911NF-04-1-0429
文摘Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.
基金the National Natural Science Foundation of China(Grant Nos.61775184 and 61875167).
文摘Based on three-level exciton model,the enhanced photonic microwave signal generation by using a sole excited-state(ES)emitting quantum dot(QD)laser under both optical injection and optical feedback is numerically studied.Within the range of period-one(P1)dynamics caused by the optical injection,the variations of microwave frequency and microwave intensity with the parameters of frequency detuning and injection strength are demonstrated.It is found that the microwave frequency can be continuously tuned by adjusting the injection parameters,and the microwave intensity can be enhanced by changing the injection strength.Moreover,considering that the generated microwave has a wide linewidth,an optical feedback loop is further employed to compress the linewidth,and the effect of feedback parameters on the linewidth is investigated.It is found that with the increase of feedback strength or delay time,the linewidth is evidently decreased due to the locking effect.However,for the relatively large feedback strength or delay time,the linewidth compression effect becomes worse due to the gradually destroyed P1 dynamics.Besides,through optimizing the feedback parameters,the linewidth can be reduced by up to more than one order of magnitude for different microwave frequencies.
基金supported by the Humanity and Social Science Foundation of Chinese Ministry of Education (No.19YJC880053)the Natural Science Foundation of Zhejiang Province (No.LQ18F010008)+3 种基金the Philosophy and Social Science Planning Project of Zhejiang Province (No.19NDJC0103YB)the Natural Science Foundation of Ningbo (No.2018A610092)the Research Fund Project of Ningbo Institute of Finance&Economics (No.1320171002)the Education and Teaching Reform Program of Ningbo Institute of Finance&Economics (No.20jyyb16)。
文摘A low phase noise millimeter-wave(MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Pérot(F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven Li Nb O3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is-112 d Bc/Hz and-106 d Bc/Hz at an offset of 1 k Hz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.
文摘In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.
基金supported by the National Key Research and Development Program of China under Grant No.2016YFB 0402302the National Natural Science Foundation of China under Grant No.91433206。
文摘Global data traffic is growing rapidly,and the demand for optoelectronic transceivers applied in data centers(DCs)is also increasing correspondingly.In this review,we first briefly introduce the development of optoelectronics transceivers in DCs,as well as the advantages of silicon photonic chips fabricated by complementary metal oxide semiconductor process.We also summarize the research on the main components in silicon photonic transceivers.In particular,quantum dot lasers have shown great potential as light sources for silicon photonic integration—whether to adopt bonding method or monolithic integration—thanks to their unique advantages over the conventional quantum-well counterparts.Some of the solutions for highspeed optical interconnection in DCs are then discussed.Among them,wavelength division multiplexing and four-level pulseamplitude modulation have been widely studied and applied.At present,the application of coherent optical communication technology has moved from the backbone network,to the metro network,and then to DCs.
基金supported by the National Natural Foundation of China (Nos. 61021064,61176065,10990103,and 61204058)the National Basic Research Program of China (No. 2011CB921201)
文摘We investigate InAs/GaAs quantum dot （QD） lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of InAs dot layers are set as 425 and 500℃, respectively. Ridge waveguide laser diodes are fabricated, and the characteristics of the QD lasers are systematically studied. The laser diodes with QDs grown at 425 ~C show better performance, such as threshold current density, output power, internal quantum efficiency, and characteristic temperature, than those with QDs grown at 500℃. This finding is ascribed to the higher QD density and more uniform size distribution of QDs achieved at 425℃.
基金supported by the National Natural Science Foundation of China(No.52272167)the Innovation Program for Quantum Science and Technology(No.2021ZD0301603).carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.
基金supported by the National Basic Research Program of China(No.2013CB632804/02)the National Natural Science Foundation of China(Nos.61376501,61404131,and 11274301)
文摘We report on a quantum dot quantum cascade detector（QD-QCD）, whose structure is derived from a QD cascade laser. In this structure, more ordered In As QD layers formed in the Stranski-Krastanow growth mode on a thin Ga As buffer layer are incorporated into the active region. This QD-QCD can operate up to room temperature with a peak detection wavelength of 5.8 μm. A responsivity of 3.1 mA/W at 160 K and a detectivity of 3.6 × 10~8 Jones at 77 K are obtained. The initial performance of the detector is promising, and, by further optimizing the growth of InA s QDs, integrated QD-quantum cascade laser/QCD applications are expected.
基金supported by the National Research Council Canada(Grant Nos.HTSN-206 and HTSN-245)by the Natural Sciences and Engineering Research Council of Canada.
文摘Microwave photonics(MWP)represents a significant optical signal processing system,standing at the confluence of microwave engineering and photonics.It presents a promising way for meeting the growing demands of contemporary communication systems,radar,sensing,and signal processing.Driving the rapid advancement of MWP are pivotal technologies such as optical frequency combs,photonic integrated circuits,and advanced modulation formats.The integration of photonic integrated circuit technology with hybrid integration techniques holds the promise of realizing MWP systems on a single chip,while comb shaping technology endows MWP systems with programmable and reconfigurable capabilities.In this paper,we present a review of our recent research,which focused on exploring the full spectrum of potential applications for quantum dash lasers in MWP systems.Leveraging principles of finite impulse response filters,our MWP system not only facilitates conventional filtering but also enables instantaneous frequency measurement and waveform generation.A distinguishing feature of MWP filters is their uniform delay.After converting it into a uniform phase difference,it underpins the development of MWP-based phase antenna array systems.Furthermore,this uniform delay finds application in time-interleaved photonic analog-to-digital conversion.
