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
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
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
A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of...A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm^2only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current densitycan be reduced remarkably compared with the free-running QD gain device.展开更多
Growing semiconductor laser sources on silicon is a crucial but challenging technology for developing photonic integrated circuits(PICs).InAs/GaAs quantum dot(Qdot)lasers have successfully circumvented the mismatch pr...Growing semiconductor laser sources on silicon is a crucial but challenging technology for developing photonic integrated circuits(PICs).InAs/GaAs quantum dot(Qdot)lasers have successfully circumvented the mismatch problem betweenⅢ–Ⅴmaterials and Ge or Si,and have demonstrated efficient laser emission.In this paper,we review dynamical characteristics of Qdot lasers epitaxially grown on Ge or Si,in comparison with those of Qdot lasers on native GaAs substrate.We discuss properties of linewidth broadening factor,laser noise and its sensitivity to optical feedback,intensity modulation,as well as mode locking operation.The investigation of these dynamical characteristics is beneficial for guiding the design of PICs in optical communications and optical computations.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
The optical performance of a grating-coupled external Continuous tuning from 1391 nm to 1468 nm is realized at cavity laser based on InAs/InP quantum dots is investigated. an injection current of 1900 mA. With the inj...The optical performance of a grating-coupled external Continuous tuning from 1391 nm to 1468 nm is realized at cavity laser based on InAs/InP quantum dots is investigated. an injection current of 1900 mA. With the injection current increasing to 2300 mA, the tuning is blue shifted to some extent to the range from 1383 nm to 1461 nm. By combining the effect of the injection current with the grating tuning, the total tuning bandwidth of the external cavity quantum-dot laser can reach up to 85 nm. The dependence of the threshold current on the tuning wavelength is also presented.展开更多
In this paper, simulation of InAs/GaAs quantum dot (QD) laser is performed based upon a set of eight rate equations for the carriers and photons in five energy states. Carrier dynamics in these lasers were under analy...In this paper, simulation of InAs/GaAs quantum dot (QD) laser is performed based upon a set of eight rate equations for the carriers and photons in five energy states. Carrier dynamics in these lasers were under analysis and the rate equations are solved using 4th order Runge-Kutta method. We have shown that by increasing injected current to the active medium of laser, switching-on and stability time of the system would decrease and power peak and stationary power will be increased. Also, emission in any state will start when the lower state is saturated and remain steady. The results including P-I characteristic curve for the ground state (GS), first excited state (ES1), second excited state (ES2) and output power of the QD laser will be presented.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
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
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 the past few decades,numerous high-performance silicon(Si)photonic devices have been demonstrated.Si,as a photonic platform,has received renewed interest in recent years.Efficient Si-basedⅢ–Ⅴquantum-dot(QDs)lase...In the past few decades,numerous high-performance silicon(Si)photonic devices have been demonstrated.Si,as a photonic platform,has received renewed interest in recent years.Efficient Si-basedⅢ–Ⅴquantum-dot(QDs)lasers have long been a goal for semiconductor scientists because of the incomparable optical properties of Ⅲ–Ⅴcompounds.Although the material dissimilarity betweenⅢ–Ⅴmaterial and Si hindered the development of monolithic integrations for over 30 years,considerable breakthroughs happened in the 2000s.In this paper,we review recent progress in the epitaxial growth of various Ⅲ–ⅤQD lasers on both offcut Si substrate and on-axis Si(001)substrate.In addition,the fundamental challenges in monolithic growth will be explained together with the superior characteristics of QDs.展开更多
A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot (QD) superluminescent diode (SLD) as the gain device. The SLD device is processed with a be...A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot (QD) superluminescent diode (SLD) as the gain device. The SLD device is processed with a bent-waveguide structure and facet antireflection (AR) coating. Tuning bandwidths of 106 nm and 117 nm are achieved under a-A and 3.5-A injection currents, respectively. The large tuning range originates essentially from the broad gain spectrum of self-assembled QDs. The bent waveguide structure combined with the facet AR coating plays a role in suppressing the inner-cavity lasing under a large injection current.展开更多
Direct epitaxial growthⅢ–Ⅴquantum dot(QD)structures on CMOS-compatible silicon substrates is considered as one of the most promising approaches to achieve low-cost and high-yield Si-based lasers for silicon photoni...Direct epitaxial growthⅢ–Ⅴquantum dot(QD)structures on CMOS-compatible silicon substrates is considered as one of the most promising approaches to achieve low-cost and high-yield Si-based lasers for silicon photonic integration.However,epitaxial growth ofⅢ–Ⅴmaterials on Si encounters the following three major challenges:high density of threading dislocations,antiphase boundaries and thermal cracks,which significantly degrade the crystal quality and potential device performance.In this review,we will focus on some recent results related to InAs/GaAs quantum dot lasers on Si(001)substrates byⅢ–Ⅴ/Ⅳhybrid epitaxial growth via(111)-faceted Si hollow structures.Moreover,by using the step-graded epitaxial growth process the emission wavelength of InAs QDs can be extended from O-band to C/L-band.High-performance InAs/GaAs QD microdisk lasers with sub-milliwatts threshold on Si(001)substrates are fabricated and characterized.The above results pave a promising path towards the on-chip lasers for optical interconnect applications.展开更多
Systematic study of molecular beam epitaxy-grown self-assembled ln(Ga)As/GaAs, In-AlAs/AlGaAs/GaAs, and InAs/InAIAs/lnP quantum dots (QDs) is demonstrated. By adjusting growth conditions, surprising alignment, prefere...Systematic study of molecular beam epitaxy-grown self-assembled ln(Ga)As/GaAs, In-AlAs/AlGaAs/GaAs, and InAs/InAIAs/lnP quantum dots (QDs) is demonstrated. By adjusting growth conditions, surprising alignment, preferential elongation, and pronounced sequential coalescence of dots under the specific condition are realized. Room-temperature (RT) continuous-wave (CW) lasing at the wavelength of 960 nm with output power of 1 W is achieved from vertical coupled InAs/GaAs QDs ensemble. The RT threshold current density is 218 A/cm2. An RT CW output power of 0.53 W ensures at least 3 000 h lasing (only drops 0.83 db). This is one of the best results ever reported.展开更多
A wide wavelength tuning range swept external-cavity laser using an In As/Ga As quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Li...A wide wavelength tuning range swept external-cavity laser using an In As/Ga As quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Littrow telescope-less configuration. The swept laser generates greater than 54-m W peak output power and up to 33-k Hz sweep rate with a sweep range of 150 nm centered at 1155 nm. The effects of injection current and sweep rate on the sweep performance of the swept laser are studied.展开更多
A mode-locked external-cavity laser emitting at 1.17-μm wavelength using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. By changing the external-cavity le...A mode-locked external-cavity laser emitting at 1.17-μm wavelength using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. By changing the external-cavity length, repetition rates of 854, 912, and 969 MHz are achieved respectively. The narrowest -3-dB radio-frequency linewidth obtained is 38 kHz, indicating that the laser is under stable mode-locking operation.展开更多
A wavelength-tunable mode-locked quantum dot laser using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. A dispersion prism, which has lower optical loss an...A wavelength-tunable mode-locked quantum dot laser using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. A dispersion prism, which has lower optical loss and less spectral narrowing than a blazed grating, is used for wavelength selection and tuning. A wavelength tuning range of 45.5 nm (from 1137.3 nm to 1182.8 nm) under 140-mA injection current in the passive mode-locked regime is achieved. The maximum average power of 19 mW is obtained at the 1170.3-nm wavelength, corresponding to the single pulse energy of 36.5 pJ.展开更多
A new Quantum Dots(Qdots) nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confoca...A new Quantum Dots(Qdots) nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope(LSCM) was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70(HSP70) in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.展开更多
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.
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 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Project supported by the National Basic Research Program of China (Grant No. 2006CB604904)the National Natural Science Foundation of China (Grant Nos. 60976057, 60876086 and 60776037)
文摘A broadband external cavity tunable laser is realized by using a broad-emitting spectral InAs/GaAs quantum dot (QD) gain device. A tuning range of 69 nm with a central wavelength of 1056 nm, is achieved at a bias of 1.25 kA/cm^2only by utilizing the light emission from the ground state of QDs. This large tunable range only covers the QD ground-state emission and is related to the inhomogeneous size distribution of QDs. No excited state contributes to the tuning bandwidth. The application of the QD gain device to the external cavity tunable laser shows its immense potential in broadening the tuning bandwidth. By the external cavity feedback, the threshold current densitycan be reduced remarkably compared with the free-running QD gain device.
基金supported by National Natural Science Foundation of China (No. 61804095)by Shanghai Pujiang Program (No. 17PJ1406500)
文摘Growing semiconductor laser sources on silicon is a crucial but challenging technology for developing photonic integrated circuits(PICs).InAs/GaAs quantum dot(Qdot)lasers have successfully circumvented the mismatch problem betweenⅢ–Ⅴmaterials and Ge or Si,and have demonstrated efficient laser emission.In this paper,we review dynamical characteristics of Qdot lasers epitaxially grown on Ge or Si,in comparison with those of Qdot lasers on native GaAs substrate.We discuss properties of linewidth broadening factor,laser noise and its sensitivity to optical feedback,intensity modulation,as well as mode locking operation.The investigation of these dynamical characteristics is beneficial for guiding the design of PICs in optical communications and optical computations.
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 Natural Science Foundation of China (Grant Nos. 61274072, 60976057, 61176047, and 60876086)
文摘The optical performance of a grating-coupled external Continuous tuning from 1391 nm to 1468 nm is realized at cavity laser based on InAs/InP quantum dots is investigated. an injection current of 1900 mA. With the injection current increasing to 2300 mA, the tuning is blue shifted to some extent to the range from 1383 nm to 1461 nm. By combining the effect of the injection current with the grating tuning, the total tuning bandwidth of the external cavity quantum-dot laser can reach up to 85 nm. The dependence of the threshold current on the tuning wavelength is also presented.
文摘In this paper, simulation of InAs/GaAs quantum dot (QD) laser is performed based upon a set of eight rate equations for the carriers and photons in five energy states. Carrier dynamics in these lasers were under analysis and the rate equations are solved using 4th order Runge-Kutta method. We have shown that by increasing injected current to the active medium of laser, switching-on and stability time of the system would decrease and power peak and stationary power will be increased. Also, emission in any state will start when the lower state is saturated and remain steady. The results including P-I characteristic curve for the ground state (GS), first excited state (ES1), second excited state (ES2) and output power of the QD laser will be presented.
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 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.
基金financial support from the UK EPSRC under grant No. EP/P006973/1the EPSRC National Epitaxy Facility European project H2020-ICT-PICTURE (780930)+2 种基金the Royal Academy of Engineering (RF201617/16/28)Investissments d’avenir (IRT Nanoelec: ANR-10-IRT-05 and Need for IoT: ANR-15-IDEX-02)the Chinese Scholarship Council for funding
文摘In the past few decades,numerous high-performance silicon(Si)photonic devices have been demonstrated.Si,as a photonic platform,has received renewed interest in recent years.Efficient Si-basedⅢ–Ⅴquantum-dot(QDs)lasers have long been a goal for semiconductor scientists because of the incomparable optical properties of Ⅲ–Ⅴcompounds.Although the material dissimilarity betweenⅢ–Ⅴmaterial and Si hindered the development of monolithic integrations for over 30 years,considerable breakthroughs happened in the 2000s.In this paper,we review recent progress in the epitaxial growth of various Ⅲ–ⅤQD lasers on both offcut Si substrate and on-axis Si(001)substrate.In addition,the fundamental challenges in monolithic growth will be explained together with the superior characteristics of QDs.
基金Project supported by the National Key Basic Research and Development Program of China (Grant No. 2006CB604904)the National Natural Science Foundation of China (Grant Nos. 60976057, 60876086, 60776037, and 10775106)
文摘A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot (QD) superluminescent diode (SLD) as the gain device. The SLD device is processed with a bent-waveguide structure and facet antireflection (AR) coating. Tuning bandwidths of 106 nm and 117 nm are achieved under a-A and 3.5-A injection currents, respectively. The large tuning range originates essentially from the broad gain spectrum of self-assembled QDs. The bent waveguide structure combined with the facet AR coating plays a role in suppressing the inner-cavity lasing under a large injection current.
基金financial support was provided by the National Natural Science Foundation of China (Nos. 61635011, 11574356, 11434010, 61804177 and 11804382)National Key Research and Development Program of China (Nos. 2016YFA0300600 and 2016YFA0301700)+1 种基金Key Research Program of Frontier Sciences, CAS (No. QYZDB-SSW-JSC009)Ting Wang was supported by the Youth Innovation Promotion Association of CAS (No. 2018011)
文摘Direct epitaxial growthⅢ–Ⅴquantum dot(QD)structures on CMOS-compatible silicon substrates is considered as one of the most promising approaches to achieve low-cost and high-yield Si-based lasers for silicon photonic integration.However,epitaxial growth ofⅢ–Ⅴmaterials on Si encounters the following three major challenges:high density of threading dislocations,antiphase boundaries and thermal cracks,which significantly degrade the crystal quality and potential device performance.In this review,we will focus on some recent results related to InAs/GaAs quantum dot lasers on Si(001)substrates byⅢ–Ⅴ/Ⅳhybrid epitaxial growth via(111)-faceted Si hollow structures.Moreover,by using the step-graded epitaxial growth process the emission wavelength of InAs QDs can be extended from O-band to C/L-band.High-performance InAs/GaAs QD microdisk lasers with sub-milliwatts threshold on Si(001)substrates are fabricated and characterized.The above results pave a promising path towards the on-chip lasers for optical interconnect applications.
文摘Systematic study of molecular beam epitaxy-grown self-assembled ln(Ga)As/GaAs, In-AlAs/AlGaAs/GaAs, and InAs/InAIAs/lnP quantum dots (QDs) is demonstrated. By adjusting growth conditions, surprising alignment, preferential elongation, and pronounced sequential coalescence of dots under the specific condition are realized. Room-temperature (RT) continuous-wave (CW) lasing at the wavelength of 960 nm with output power of 1 W is achieved from vertical coupled InAs/GaAs QDs ensemble. The RT threshold current density is 218 A/cm2. An RT CW output power of 0.53 W ensures at least 3 000 h lasing (only drops 0.83 db). This is one of the best results ever reported.
基金Project supported by the National Natural Science Foundation of China(Grant No.61274072)the National High Technology Research and Development Program of China(Grant No.2013AA014201)
文摘A wide wavelength tuning range swept external-cavity laser using an In As/Ga As quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Littrow telescope-less configuration. The swept laser generates greater than 54-m W peak output power and up to 33-k Hz sweep rate with a sweep range of 150 nm centered at 1155 nm. The effects of injection current and sweep rate on the sweep performance of the swept laser are studied.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61274072,60976057,and 60876086)
文摘A mode-locked external-cavity laser emitting at 1.17-μm wavelength using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. By changing the external-cavity length, repetition rates of 854, 912, and 969 MHz are achieved respectively. The narrowest -3-dB radio-frequency linewidth obtained is 38 kHz, indicating that the laser is under stable mode-locking operation.
基金Project supported by the National Natural Science Foundation of China(Grant No.61274072)the National High Technology Research and Development Program of China(Grant No.2013AA014201)
文摘A wavelength-tunable mode-locked quantum dot laser using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. A dispersion prism, which has lower optical loss and less spectral narrowing than a blazed grating, is used for wavelength selection and tuning. A wavelength tuning range of 45.5 nm (from 1137.3 nm to 1182.8 nm) under 140-mA injection current in the passive mode-locked regime is achieved. The maximum average power of 19 mW is obtained at the 1170.3-nm wavelength, corresponding to the single pulse energy of 36.5 pJ.
基金Funded by the National Natural Science Foundation of China (No.303711325)
文摘A new Quantum Dots(Qdots) nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope(LSCM) was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70(HSP70) in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.