The emerging new concepts and technologies based on microwave photonics have led to an ever-increasing interest in developing innovative radar systems with a net gain in functionality,bandwidth /resolution,size,mass,c...The emerging new concepts and technologies based on microwave photonics have led to an ever-increasing interest in developing innovative radar systems with a net gain in functionality,bandwidth /resolution,size,mass,complexity and cost when compared with the traditional implementations. This paper describes the techniques developed in the last few years in microwave photonics that might revolutionize the way to design multifunction radar systems,with an emphasis on the recent advances in optoelectronic oscillators( OEOs),arbitrary waveform generation,photonic mixing,phase coding,filtering,beamforming,analog-to-digital conversion,and stable radio-frequency signal transfer. Challenges in implementation of these components and subsystems for meeting the technique requirements of the multifunction radar applications are discussed.展开更多
Microwave photonics (MWP) is an interdisci- plinary field that combines two different areas of microwave engineering and photonics. It has several key features by transferring signals between the optical domain and ...Microwave photonics (MWP) is an interdisci- plinary field that combines two different areas of microwave engineering and photonics. It has several key features by transferring signals between the optical domain and microwave domain, which leads to the advantages of broad operation bandwidth for generation, processing and distribution of microwave signals and high resolution for optical spectrum measurement. In this paper, we comprehensively review past and current status of MWP in China by introducing the representative works from most of the active MWP research groups. Future prospective is also discussed fi'om the national strategy to key enabling technology that we have developed.展开更多
The explosive volume growth of deep-learning(DL)applications has triggered an era in computing,with neuromorphic photonic platforms promising to merge ultra-high speed and energy efficiency credentials with the brain-...The explosive volume growth of deep-learning(DL)applications has triggered an era in computing,with neuromorphic photonic platforms promising to merge ultra-high speed and energy efficiency credentials with the brain-inspired computing primitives.The transfer of deep neural networks(DNNs)onto silicon photonic(SiPho)architectures requires,however,an analog computing engine that can perform tiled matrix multiplication(TMM)at line rate to support DL applications with a large number of trainable parameters,similar to the approach followed by state-of-the-art electronic graphics processing units.Herein,we demonstrate an analog SiPho computing engine that relies on a coherent architecture and can perform optical TMM at the record-high speed of 50 GHz.Its potential to support DL applications,where the number of trainable parameters exceeds the available hardware dimensions,is highlighted through a photonic DNN that can reliably detect distributed denial-of-service attacks within a data center with a Cohen’s kappa score-based accuracy of 0.636.展开更多
This paper reviews the work done by research- ers at INRS and UBC in the field of integrated microwave photonics (IMWPs) using silicon based waveguide Bragg gratings (WBGs). The grating design methodology is discu...This paper reviews the work done by research- ers at INRS and UBC in the field of integrated microwave photonics (IMWPs) using silicon based waveguide Bragg gratings (WBGs). The grating design methodology is discussed in detail, including practical device fabrication considerations. On-chip implementations of various fun- darnental photonic signal processing units, including Fourier transformers, Hilbert transformers, ultrafast pulse shapers etc., are reviewed. Recent progress on WBGs- based IMWP subsystems, such as true time delay elements, phase shifters, real time frequency identification systems, is also discussed.展开更多
Microresonator frequency combs (microcombs) are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the s...Microresonator frequency combs (microcombs) are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the study of microcombs to reveal and control the comb formation dynamics. In this paper, we reviewed the microwave photonic techniques and applications that are connected with microcombs. The future research directions of microcomb-based microwave photonics were also discussed.展开更多
Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent pr...Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent progress of a few promising contenders for on-chip light sources in terms of operating wavelength,pump condition,power consumption,and fabrication process.Additionally,the performance of each contender is also assessed with respect to thermal stability,which is a crucial parameter to consider in complex optoelectronic integrated circuits(OEICs)and optical interconnections.Currently,III-V-based silicon(Si)lasers formed via bonding techniques demonstrate the best performance and display the best opportunity for commercial usage in the near future.However,in the long term,direct hetero-epitaxial growth of III–V materials on Si seems more promising for low-cost,high-yield fabrication.The demonstration of high-performance quantum dot(QD)lasers monolithically grown on Si strongly forecasts its feasibility and enormous potential for on-chip lasers.The superior temperature-insensitive characteristics of the QD laser promote this design in large-scale high-density OEICs.The Germanium(Ge)-on-Si laser is also competitive for large-scale monolithic integration in the future.Compared with a III-V-based Si laser,the biggest potential advantage of a Ge-on-Si laser lies in its material and processing compatibility with Si technology.Additionally,the versatility of Ge facilitates photon emission,modulation,and detection simultaneously with a simple process complexity and low cost.展开更多
Photonic integrated circuits are developing as key enabling components for high-performance computing and advanced networkon-chip,as well as other emerging technologies such as lab-on-chip sensors,with relevant applic...Photonic integrated circuits are developing as key enabling components for high-performance computing and advanced networkon-chip,as well as other emerging technologies such as lab-on-chip sensors,with relevant applications in areas from medicine and biotechnology to aerospace.These demanding applications will require novel features,such as dynamically reconfigurable light pathways,obtained by properly harnessing on-chip optical radiation.In this paper,we introduce a broadband,high directivity(4150),low loss and reconfigurable silicon photonics nanoantenna that fully enables on-chip radiation control.We propose the use of these nanoantennas as versatile building blocks to develop wireless(unguided)silicon photonic devices,which considerably enhance the range of achievable integrated photonic functionalities.As examples of applications,we demonstrate 160 Gbit s−1 data transmission over mm-scale wireless interconnects,a compact low-crosstalk 12-port crossing and electrically reconfigurable pathways via optical beam steering.Moreover,the realization of a flow micro-cytometer for particle characterization demonstrates the smart system integration potential of our approach as lab-on-chip devices.展开更多
By combining a silicon-based lithium niobate modulator and a silicon-based Si3N4resonator with silicon-based photonics technology,a highly systematic design of a hybrid integrated optical gyroscope with enhanced recip...By combining a silicon-based lithium niobate modulator and a silicon-based Si3N4resonator with silicon-based photonics technology,a highly systematic design of a hybrid integrated optical gyroscope with enhanced reciprocity sensitivity and a dual micro-ring structure is proposed for the first time in this paper.The relationship between the device's structural parameters and optical performance is also analyzed by constructing a complete simulation link,which provides a theoretical design reference to improve the system's sensitivity.When the wavelength is 1550 nm,the conversion frequency of the dual-ring optical path is 50 MHz,the coupling coefficient is 0.2,and the radius R is 1000μm,the quality factor of the silicon-based Si_(3)N_(4)resonator is 2.58×10^(5),which is 1.58 times that of the silicon-on-insulator resonator.Moreover,the effective number of times the light travels around the ring before leaving the micro-ring is 5.93,which is 1.62 times that of the silicon-on-insulator resonator.The work fits the gyro dynamic output diagram,and solves the problem of low sensitivity at low speed by setting the phase offset.This results provide a basis for the further optimization of design and chip processing of the integrated optical gyroscope.展开更多
In recent decades,silicon photonics has attracted much attention in telecom and data-com areas.Constituted of high refractive-index contrast waveguides on silicon-on-insulator(SOI),a variety of integrated photonic pas...In recent decades,silicon photonics has attracted much attention in telecom and data-com areas.Constituted of high refractive-index contrast waveguides on silicon-on-insulator(SOI),a variety of integrated photonic passive and active devices have been implemented supported by excellent optical properties of silicon in the mid-infrared spectrum.The main advantage of the silicon photonics is the ability to use complementary metal oxide semiconductor(CMOS)process-compatible fabrication technologies,resulting in high-volume production at low cost.On the other hand,explosively growing traffic in the telecom,data center and high-performance computer demands the data flow to have high speed,wide bandwidth,low cost,and high energy-efficiency,as well as the photonics and electronics to be integrated for ultra-fast data transfer in networks.In practical applications,silicon photonics started with optical interconnect transceivers in the data-com first,and has been now extended to innovative applications such as multi-port optical switches in the telecom network node and integrated optical phased arrays(OPAs)in light detection and ranging(LiDAR).This paper overviews the progresses of silicon photonics from four points reflecting the recent advances mentioned above.CMOS-based silicon photonic platform technologies,applications to optical transceiver in the data-com network,applications to multi-port optical switches in the telecom network and applications to OPA in LiDAR system.展开更多
In recent years,space-division multiplexing(SDM)technology,which involves transmitting data information on multiple parallel channels for efficient capacity scaling,has been widely used in fiber and free-space optical...In recent years,space-division multiplexing(SDM)technology,which involves transmitting data information on multiple parallel channels for efficient capacity scaling,has been widely used in fiber and free-space optical communication sys-tems.To enable flexible data management and cope with the mixing between different channels,the integrated reconfig-urable optical processor is used for optical switching and mitigating the channel crosstalk.However,efficient online train-ing becomes intricate and challenging,particularly when dealing with a significant number of channels.Here we use the stochastic parallel gradient descent(SPGD)algorithm to configure the integrated optical processor,which has less com-putation than the traditional gradient descent(GD)algorithm.We design and fabricate a 6×6 on-chip optical processor on silicon platform to implement optical switching and descrambling assisted by the online training with the SPDG algorithm.Moreover,we apply the on-chip processor configured by the SPGD algorithm to optical communications for optical switching and efficiently mitigating the channel crosstalk in SDM systems.In comparison with the traditional GD al-gorithm,it is found that the SPGD algorithm features better performance especially when the scale of matrix is large,which means it has the potential to optimize large-scale optical matrix computation acceleration chips.展开更多
We report an 8-channel wavelength-mode optical pulse interleaver on a silicon photonic chip.Wavelength-and mode-division multiplexing techniques are combined to increase the repetition rate of the pulses without addin...We report an 8-channel wavelength-mode optical pulse interleaver on a silicon photonic chip.Wavelength-and mode-division multiplexing techniques are combined to increase the repetition rate of the pulses without adding the complexity of a single dimension.The interleaver uses a cascaded Mach–Zehnder interferometer architecture as a wavelength-division(de)multiplexer,an asymmetric directional coupler as a mode(de)multiplexer,and various lengths of silicon waveguides as delay lines.A pulse sequence with a time interval of 125 ps is implemented with the repetition rate being eight times that of the initial one.The demonstrated wavelength-mode multiplexing approach opens a new route for the generation of high-speed optical pulses.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
作为硅光子集成芯片中基本无源器件的硅基光波导是进行光信号传输的通道,其具有良好的性能,且与CMOS(Complementary Metal Oxide Semiconductor)工艺相兼容因而得到广泛应用。用于电信和数据中心的硅光子集成电路已逐步走向商业化。近年...作为硅光子集成芯片中基本无源器件的硅基光波导是进行光信号传输的通道,其具有良好的性能,且与CMOS(Complementary Metal Oxide Semiconductor)工艺相兼容因而得到广泛应用。用于电信和数据中心的硅光子集成电路已逐步走向商业化。近年来,中红外波段在自由空间通信、传感以及环境监测等领域的潜在应用受到研究者们的广泛关注。文中分析了中红外硅基光波导的研究现状,归纳了SOI(Silicon on Insulator)、GOSI(Ge-on-SOI)、SOS(Si on Sapphire)、GOS(Ge-on-Si)、SGOS(SiGe-on-Si)、SON(Si-on Si_(3)N_(4))、GON(Ge-on Si_(3)N_(4))等波导材料平台和SOPS(Si on Porous Si)、Undercut、Pedestal、Freestanding、Suspended、LOCOS(Local Oxidation of Silicon)以及等离子体结构等制造工艺平台的研究成果。迄今为止,多数单晶硅在MIR(Mid-Infrared)平台的传播损耗大约在0.7~3.0 dB·cm^(-1)。文中讨论并对比了不同类型波导的应用前景,为中红外硅基光波导的研发、应用和商业化提供了参考。展开更多
基金Supported in part by the National Basic Research Program of China(2012CB315705)the Natural Science Foundation of Jiangsu Province(BK2012031,BK2012381)+1 种基金the National Natural Science Foundation of China(61201048,61107063)the Fundamental Research Funds for the Central Universities
文摘The emerging new concepts and technologies based on microwave photonics have led to an ever-increasing interest in developing innovative radar systems with a net gain in functionality,bandwidth /resolution,size,mass,complexity and cost when compared with the traditional implementations. This paper describes the techniques developed in the last few years in microwave photonics that might revolutionize the way to design multifunction radar systems,with an emphasis on the recent advances in optoelectronic oscillators( OEOs),arbitrary waveform generation,photonic mixing,phase coding,filtering,beamforming,analog-to-digital conversion,and stable radio-frequency signal transfer. Challenges in implementation of these components and subsystems for meeting the technique requirements of the multifunction radar applications are discussed.
基金We would like to thank all the colleagues who have been involved into these reported works in China and collaborated internationally. We would like to thank the supporting of the National High-Tech Research & Development Program of China (Nos. 2011AA010303, 2013AA014201 and 2011AA010305) and the National Natural Science Foundation of China (Grant Nos, 61177080, 61377002, 61321063 and 61090391). Ming Li was supported in part by the "Thousand Young Talent" program.
文摘Microwave photonics (MWP) is an interdisci- plinary field that combines two different areas of microwave engineering and photonics. It has several key features by transferring signals between the optical domain and microwave domain, which leads to the advantages of broad operation bandwidth for generation, processing and distribution of microwave signals and high resolution for optical spectrum measurement. In this paper, we comprehensively review past and current status of MWP in China by introducing the representative works from most of the active MWP research groups. Future prospective is also discussed fi'om the national strategy to key enabling technology that we have developed.
基金the EU-projects PlasmoniAC(Grant No.871391)SIPHO-G(Grant No.101017194)Hellenic Foundation for Research and Innovation(H.F.R.I.)under the“First Call for H.F.R.I.Research Projects to Support Faculty Members and Researchers and the Procurement of High-cost Research Equipment Grant”(Grant No.4233,DeepLight).
文摘The explosive volume growth of deep-learning(DL)applications has triggered an era in computing,with neuromorphic photonic platforms promising to merge ultra-high speed and energy efficiency credentials with the brain-inspired computing primitives.The transfer of deep neural networks(DNNs)onto silicon photonic(SiPho)architectures requires,however,an analog computing engine that can perform tiled matrix multiplication(TMM)at line rate to support DL applications with a large number of trainable parameters,similar to the approach followed by state-of-the-art electronic graphics processing units.Herein,we demonstrate an analog SiPho computing engine that relies on a coherent architecture and can perform optical TMM at the record-high speed of 50 GHz.Its potential to support DL applications,where the number of trainable parameters exceeds the available hardware dimensions,is highlighted through a photonic DNN that can reliably detect distributed denial-of-service attacks within a data center with a Cohen’s kappa score-based accuracy of 0.636.
文摘This paper reviews the work done by research- ers at INRS and UBC in the field of integrated microwave photonics (IMWPs) using silicon based waveguide Bragg gratings (WBGs). The grating design methodology is discussed in detail, including practical device fabrication considerations. On-chip implementations of various fun- darnental photonic signal processing units, including Fourier transformers, Hilbert transformers, ultrafast pulse shapers etc., are reviewed. Recent progress on WBGs- based IMWP subsystems, such as true time delay elements, phase shifters, real time frequency identification systems, is also discussed.
基金This work was supported in part by the Air Force Office of Scientific Research under grant FA9550-15-1-0211, from the DARPA PULSE program through grant W31P40-13-1-0018 from AMR- DEC, and from the National Science Foundation under grant ECCS- 1509578.
文摘Microresonator frequency combs (microcombs) are very promising as ultra-compact broadband sources for microwave photonic applications. Conversely, microwave photonic techniques are also employed inten- sely in the study of microcombs to reveal and control the comb formation dynamics. In this paper, we reviewed the microwave photonic techniques and applications that are connected with microcombs. The future research directions of microcomb-based microwave photonics were also discussed.
基金This work was partially supported by the Major International Cooperation and Exchange Program of the National Natural Science Foundation of China under Grant 61120106012the Peking University 985 Startup Fund.
文摘Serving as the electrical to optical converter,the on-chip silicon light source is an indispensable component of silicon photonic technologies and has long been pursued.Here,we briefly review the history and recent progress of a few promising contenders for on-chip light sources in terms of operating wavelength,pump condition,power consumption,and fabrication process.Additionally,the performance of each contender is also assessed with respect to thermal stability,which is a crucial parameter to consider in complex optoelectronic integrated circuits(OEICs)and optical interconnections.Currently,III-V-based silicon(Si)lasers formed via bonding techniques demonstrate the best performance and display the best opportunity for commercial usage in the near future.However,in the long term,direct hetero-epitaxial growth of III–V materials on Si seems more promising for low-cost,high-yield fabrication.The demonstration of high-performance quantum dot(QD)lasers monolithically grown on Si strongly forecasts its feasibility and enormous potential for on-chip lasers.The superior temperature-insensitive characteristics of the QD laser promote this design in large-scale high-density OEICs.The Germanium(Ge)-on-Si laser is also competitive for large-scale monolithic integration in the future.Compared with a III-V-based Si laser,the biggest potential advantage of a Ge-on-Si laser lies in its material and processing compatibility with Si technology.Additionally,the versatility of Ge facilitates photon emission,modulation,and detection simultaneously with a simple process complexity and low cost.
文摘Photonic integrated circuits are developing as key enabling components for high-performance computing and advanced networkon-chip,as well as other emerging technologies such as lab-on-chip sensors,with relevant applications in areas from medicine and biotechnology to aerospace.These demanding applications will require novel features,such as dynamically reconfigurable light pathways,obtained by properly harnessing on-chip optical radiation.In this paper,we introduce a broadband,high directivity(4150),low loss and reconfigurable silicon photonics nanoantenna that fully enables on-chip radiation control.We propose the use of these nanoantennas as versatile building blocks to develop wireless(unguided)silicon photonic devices,which considerably enhance the range of achievable integrated photonic functionalities.As examples of applications,we demonstrate 160 Gbit s−1 data transmission over mm-scale wireless interconnects,a compact low-crosstalk 12-port crossing and electrically reconfigurable pathways via optical beam steering.Moreover,the realization of a flow micro-cytometer for particle characterization demonstrates the smart system integration potential of our approach as lab-on-chip devices.
基金Project supported by the science and technology general project of Beijing Municipal Education Commission(Grant No.KM202111232019)Beijing Municipal Natural Science Foundation(Grant No.2214058)+4 种基金the Discipline Innovation Program of Higher Education(Grant No.D17021)the Open Project of the State Key Laboratory of Integrated Optoelectronics(Grant No.IOSKL2020KF22)Beijing Great Wall Scholars Program(Grant No.CIT&TCD20190323)the National Natural Science Foundation of China(Grant No.61875237)Beijing Youth Talent Support Program(Grant No.Z2019042)。
文摘By combining a silicon-based lithium niobate modulator and a silicon-based Si3N4resonator with silicon-based photonics technology,a highly systematic design of a hybrid integrated optical gyroscope with enhanced reciprocity sensitivity and a dual micro-ring structure is proposed for the first time in this paper.The relationship between the device's structural parameters and optical performance is also analyzed by constructing a complete simulation link,which provides a theoretical design reference to improve the system's sensitivity.When the wavelength is 1550 nm,the conversion frequency of the dual-ring optical path is 50 MHz,the coupling coefficient is 0.2,and the radius R is 1000μm,the quality factor of the silicon-based Si_(3)N_(4)resonator is 2.58×10^(5),which is 1.58 times that of the silicon-on-insulator resonator.Moreover,the effective number of times the light travels around the ring before leaving the micro-ring is 5.93,which is 1.62 times that of the silicon-on-insulator resonator.The work fits the gyro dynamic output diagram,and solves the problem of low sensitivity at low speed by setting the phase offset.This results provide a basis for the further optimization of design and chip processing of the integrated optical gyroscope.
文摘In recent decades,silicon photonics has attracted much attention in telecom and data-com areas.Constituted of high refractive-index contrast waveguides on silicon-on-insulator(SOI),a variety of integrated photonic passive and active devices have been implemented supported by excellent optical properties of silicon in the mid-infrared spectrum.The main advantage of the silicon photonics is the ability to use complementary metal oxide semiconductor(CMOS)process-compatible fabrication technologies,resulting in high-volume production at low cost.On the other hand,explosively growing traffic in the telecom,data center and high-performance computer demands the data flow to have high speed,wide bandwidth,low cost,and high energy-efficiency,as well as the photonics and electronics to be integrated for ultra-fast data transfer in networks.In practical applications,silicon photonics started with optical interconnect transceivers in the data-com first,and has been now extended to innovative applications such as multi-port optical switches in the telecom network node and integrated optical phased arrays(OPAs)in light detection and ranging(LiDAR).This paper overviews the progresses of silicon photonics from four points reflecting the recent advances mentioned above.CMOS-based silicon photonic platform technologies,applications to optical transceiver in the data-com network,applications to multi-port optical switches in the telecom network and applications to OPA in LiDAR system.
基金supported by the National Natural Science Foundation of China(NSFC)(62125503,62261160388)the Natural Science Foundation of Hubei Province of China(2023AFA028)the Innovation Project of Optics Valley Laboratory(OVL2021BG004).
文摘In recent years,space-division multiplexing(SDM)technology,which involves transmitting data information on multiple parallel channels for efficient capacity scaling,has been widely used in fiber and free-space optical communication sys-tems.To enable flexible data management and cope with the mixing between different channels,the integrated reconfig-urable optical processor is used for optical switching and mitigating the channel crosstalk.However,efficient online train-ing becomes intricate and challenging,particularly when dealing with a significant number of channels.Here we use the stochastic parallel gradient descent(SPGD)algorithm to configure the integrated optical processor,which has less com-putation than the traditional gradient descent(GD)algorithm.We design and fabricate a 6×6 on-chip optical processor on silicon platform to implement optical switching and descrambling assisted by the online training with the SPDG algorithm.Moreover,we apply the on-chip processor configured by the SPGD algorithm to optical communications for optical switching and efficiently mitigating the channel crosstalk in SDM systems.In comparison with the traditional GD al-gorithm,it is found that the SPGD algorithm features better performance especially when the scale of matrix is large,which means it has the potential to optimize large-scale optical matrix computation acceleration chips.
文摘We report an 8-channel wavelength-mode optical pulse interleaver on a silicon photonic chip.Wavelength-and mode-division multiplexing techniques are combined to increase the repetition rate of the pulses without adding the complexity of a single dimension.The interleaver uses a cascaded Mach–Zehnder interferometer architecture as a wavelength-division(de)multiplexer,an asymmetric directional coupler as a mode(de)multiplexer,and various lengths of silicon waveguides as delay lines.A pulse sequence with a time interval of 125 ps is implemented with the repetition rate being eight times that of the initial one.The demonstrated wavelength-mode multiplexing approach opens a new route for the generation of high-speed optical pulses.
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.
文摘作为硅光子集成芯片中基本无源器件的硅基光波导是进行光信号传输的通道,其具有良好的性能,且与CMOS(Complementary Metal Oxide Semiconductor)工艺相兼容因而得到广泛应用。用于电信和数据中心的硅光子集成电路已逐步走向商业化。近年来,中红外波段在自由空间通信、传感以及环境监测等领域的潜在应用受到研究者们的广泛关注。文中分析了中红外硅基光波导的研究现状,归纳了SOI(Silicon on Insulator)、GOSI(Ge-on-SOI)、SOS(Si on Sapphire)、GOS(Ge-on-Si)、SGOS(SiGe-on-Si)、SON(Si-on Si_(3)N_(4))、GON(Ge-on Si_(3)N_(4))等波导材料平台和SOPS(Si on Porous Si)、Undercut、Pedestal、Freestanding、Suspended、LOCOS(Local Oxidation of Silicon)以及等离子体结构等制造工艺平台的研究成果。迄今为止,多数单晶硅在MIR(Mid-Infrared)平台的传播损耗大约在0.7~3.0 dB·cm^(-1)。文中讨论并对比了不同类型波导的应用前景,为中红外硅基光波导的研发、应用和商业化提供了参考。