Why integratingⅢ–Ⅴsemiconductor on silicon Photonics is an enabling technology and play a significant role in today’s information age.In the last few decades,starting from the fiber long haul optical communication...Why integratingⅢ–Ⅴsemiconductor on silicon Photonics is an enabling technology and play a significant role in today’s information age.In the last few decades,starting from the fiber long haul optical communications,optical interconnects have gradually replaced copper interconnects due to its advantage of the bandwidth distance product.As photonics is moving closer and closer to the processor and memory of computers,and eventually,to on-chip level,silicon photonics becomes a viable solution for future optical interconnections due to the feasibility of high-bandwidth,high-density I/O capability and dense integration enabled by the high index contrast.展开更多
Thin-film lithium niobate is a promising material platform for integrated nonlinear photonics,due to its high refractive index contrast with the excellent optical properties.However,the high refractive index contrast ...Thin-film lithium niobate is a promising material platform for integrated nonlinear photonics,due to its high refractive index contrast with the excellent optical properties.However,the high refractive index contrast and correspondingly small mode field diameter limit the attainable coupling between the waveguide and fiber.In second harmonic generation processes,lack of efficient fiber-chip coupling schemes covering both the fundamental and second harmonic wavelengths has greatly limited the overall efficiency.We design and fabricate an ultra-broadband tri-layer edge coupler with a high coupling efficiency.The coupler allows efficient coupling of 1 dB∕facet at 1550 nm and 3 dB∕facet at 775 nm.This enables us to achieve an ultrahigh overall second harmonic generation normalized efficiency(fiber-to-fiber)of 1027%W^(−1)cm^(−2)(on-chip second harmonic efficiency∼3256%W^(−1)cm^(−2))in a 5-mm-long periodically-poled lithium niobate waveguide,which is two to three orders of magnitude higher than that in state-of-the-art devices.展开更多
Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFL...Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFLN)photonic integrated circuit(PIC)to realize a Fourier domain mode-locked optoelectronic oscillator(FDML OEO)for generating high-precision LCMW signals.This integrated chip combines a phase modulator(PM)and an electrically tuned notch micro-ring resonator(MRR),which functions as a rapidly tunable bandpass filter,facilitating the essential phase-to-intensity modulation(PM-IM)conversion for OEO oscillation.By synchronizing the modulation period of the applied driving voltage to the MRR with the OEO loop delay,we achieve Fourier domain mode-locking,producing LCMW signals with an impressive tunable center frequency range of18.55 GHz to 23.59 GHz,an adjustable sweep bandwidth from 3.85 GHz to 8.5 GHz,and a remarkable chirp rate up to 3.22 GHz/μs.Unlike conventional PM-IM based FDML OEOs,our device obviates the need for expensive tunable lasers or microwave sources,positioning it as a practical solution for generating high-frequency LCMW signals with extended sweep bandwidth and high chirp rates,all within a compact and cost-efficient form factor.展开更多
High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonl...High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonlinearity of modulator materials,the complexity of external control devices,the bulkiness of structures,and bandwidth limitations.In this study,we present an integrated thin-film lithium niobate(TFLN)linear Mach–Zehnder modulator(LMZM),showing,to our knowledge,a record-high spurious-free dynamic range(SFDR)of 121.7 dB·Hz^(4∕5)at 1 GHz with an optical power(OP)of 5.5 dBm into the photodetector(PD),based on a widebandwidth(>50 GHz)dual-optical-mode(TE0 and TE1)co-modulated configuration with just one RF input.Additionally,compared to conventional MZMs(CMZMs),the LMZM exhibits a>10.6-dB enhancement in SFDR with an OP of>−8 dBm at 1 GHz,and maintains a 6.07-dB SFDR improvement even at 20 GHz with an OP of 0 dBm.The novel LMZM,featuring high linearity,wide bandwidth,structural simplicity,and high integration,holds significant potential as a key component in future large-scale and high-performance MWP integrated circuits.展开更多
Integrated optoelectronic chips working in the visible spectrum range have promising applications in augmented reality and virtual reality,quantum information processing,biosensors,and more.A silicon nitride optical p...Integrated optoelectronic chips working in the visible spectrum range have promising applications in augmented reality and virtual reality,quantum information processing,biosensors,and more.A silicon nitride optical phased array(OPA)can shape and steer light to enable these applications on a compact chip without moving parts.However,smaller wavelength,waveguide size,and the thermo-optic coefficient pose challenges in processing,calibration,and control of silicon nitride OPA chips.In this work,a high-speed phase control system for 532 nm silicon nitride OPA,utilizing a field programmable gate array and a digital-to-analog converter,achieves a 7.4μs voltage configuration.With this system,the single-shot multivoltage optimization of beam calibration of the OPA for tens of milliseconds is realized,and the beam scanning in the range of ±24° is demonstrated.The system fully meets the needs of high-speed scanning of silicon nitride OPA,advancing OPA's development and applications.展开更多
High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky opti...High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.展开更多
Integrated traveling-wave lithium niobate modulators need relatively large device lengths to achieve low drive voltage. To increase modulation efficiency within a compact footprint, we report an integrated Fabry–Pero...Integrated traveling-wave lithium niobate modulators need relatively large device lengths to achieve low drive voltage. To increase modulation efficiency within a compact footprint, we report an integrated Fabry–Perot-type electro-optic thin film lithium niobate on insulator modulator comprising a phase modulation region sandwiched between two distributed Bragg reflectors. The device exhibits low optical loss and a high tuning efficiency of 15.7 pm/V. We also confirm the modulator's high-speed modulation performance by non-return-to-zero modulation with a data rate up to 56 Gbit/s.展开更多
Space-division multiplexing(SDM),as a main candidate for future ultra-high capacity fibre-optic communications,needs to address limitations to its scalability imposed by computation-intensive multi-input multi-output(...Space-division multiplexing(SDM),as a main candidate for future ultra-high capacity fibre-optic communications,needs to address limitations to its scalability imposed by computation-intensive multi-input multi-output(MIMO)digital signal processing(DSP)required to eliminate the crosstalk caused by optical coupling between multiplexed spatial channels.By exploiting the unique propagation characteristics of orbital angular momentum(OAM)modes in ring core fibres(RCFs),a system that combines SDM and C+L band dense wavelength-division multiplexing(DWDM)in a 34 km 7-core RCF is demonstrated to transport a total of 24960 channels with a raw(net)capacity of 1.223(1.02)Peta-bit s−1(Pbps)and a spectral efficiency of 156.8(130.7)bit s−1 Hz−1.Remarkably for such a high channel count,the system only uses fixed-size 4×4 MIMO DSP modules with no more than 25 time-domain taps.Such ultra-low MIMO complexity is enabled by the simultaneous weak coupling among fibre cores and amongst non-degenerate OAM mode groups within each core that have a fixed number of 4 modes.These results take the capacity of OAM-based fibre-optic communications links over the 1 Pbps milestone for the first time.They also simultaneously represent the lowest MIMO complexity and the 2nd smallest fibre cladding diameter amongst reported few-mode multicore-fibre(FM-MCF)SDM systems of>1 Pbps capacity.We believe these results represent a major step forward in SDM transmission,as they manifest the significant potentials for further up-scaling the capacity per optical fibre whilst keeping MIMO processing to an ultra-low complexity level and in a modularly expandable fashion.展开更多
Optical modulators have been and will continue to be essential devices for energy-and cost-efficient optical communication networks.Heterogeneous silicon and lithium niobate modulators have demonstrated promising perf...Optical modulators have been and will continue to be essential devices for energy-and cost-efficient optical communication networks.Heterogeneous silicon and lithium niobate modulators have demonstrated promising performances of low optical loss,low drive voltage,and large modulation bandwidth.However,DC bias drift is a major drawback of optical modulators using lithium niobate as the active electro-optic material.Here,we demonstrate high-speed and bias-drift-free Mach–Zehnder modulators based on the heterogeneous silicon and lithium niobate platform.The devices combine stable thermo-optic DC biases in silicon and ultra-fast electro-optic modulation in lithium niobate,and exhibit a low insertion loss of 1.8 d B,a low half-wave voltage of 3 V,an electro-optic modulation bandwidth of at least 70 GHz,and modulation data rates up to 128 Gb/s.展开更多
Integrated photonics provides a route to both miniaturization of quantum key distribution(QKD)devices and enhancing their performance.A key element for achieving discrete-variable QKD is a singlephoton detector.It is ...Integrated photonics provides a route to both miniaturization of quantum key distribution(QKD)devices and enhancing their performance.A key element for achieving discrete-variable QKD is a singlephoton detector.It is highly desirable to integrate detectors onto a photonic chip to enable the realization of practical and scalable quantum networks.We realize a heterogeneously integrated,superconducting silicon-photonic chip.Harnessing the unique high-speed feature of our optical waveguide-integrated superconducting detector,we perform the first optimal Bell-state measurement(BSM)of time-bin encoded qubits generated from two independent lasers.The optimal BSM enables an increased key rate of measurement-device-independent QKD(MDI-QKD),which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays.Together with the timemultiplexed technique,we have enhanced the sifted key rate by almost one order of magnitude.With a 125-MHz clock rate,we obtain a secure key rate of 6.166 kbps over 24.0 dB loss,which is comparable to the state-of-the-art MDI-QKD experimental results with a GHz clock rate.Combined with integrated QKD transmitters,a scalable,chip-based,and cost-effective QKD network should become realizable in the near future.展开更多
We study the effect of dimension variation for second-harmonic generation(SHG) in lithium niobate on insulator(LNOI)waveguides. Non-trivial SHG profiles in both type-0 and type-I quasi-phase matching are observed duri...We study the effect of dimension variation for second-harmonic generation(SHG) in lithium niobate on insulator(LNOI)waveguides. Non-trivial SHG profiles in both type-0 and type-I quasi-phase matching are observed during the wavelength tuning of the fundamental light. Theoretical modeling shows that the SHG profile and efficiency can be greatly affected by the waveguide cross-section dimension variations, especially the thickness variations. In particular, our analysis shows that a thickness variation of tens of nanometers is in good agreement with the experimental results. Such investigations could be used to evaluate fabrication performance of LNOI-based nonlinear optical devices.展开更多
We propose and demonstrate a polarization diversity two-dimensional grating coupler based on the lithium niobate on insulator platform, for the first time, to the best of our knowledge. The optimization design, perfor...We propose and demonstrate a polarization diversity two-dimensional grating coupler based on the lithium niobate on insulator platform, for the first time, to the best of our knowledge. The optimization design, performance characteristics,and fabrication tolerance of the two-dimensional grating coupler are thoroughly analyzed utilizing the three-dimensional finite-difference time-domain method. Experimentally,-7.2 d B of coupling efficiency is achieved with 1 d B bandwidth of64 nm. The polarization-dependent loss is about 0.4 d B around 1550 nm. Our work provides new polarization multiplexing approaches for the lithium niobate on insulator platform, paving the way for critical applications such as high-speed polarization multiplexed electro-optical modulators.展开更多
A tunable optical delay line(ODL) featuring high switching speed and low optical loss is highly desirable in many fields. Here, based on the thin-film lithium niobate platform, we demonstrate a digitally tunable on-ch...A tunable optical delay line(ODL) featuring high switching speed and low optical loss is highly desirable in many fields. Here, based on the thin-film lithium niobate platform, we demonstrate a digitally tunable on-chip ODL that includes five Mach–Zehnder interferometer optical switches, four flip-chip photodetectors, and four delayline waveguides. The proposed optical switches can achieve a switching speed of 13 ns and an extinction ratio of34.9 dB. Using a modified Euler-bend-based spiral structure, the proposed delay-line waveguide can simultaneously achieve a small footprint and low optical propagation loss. The proposed ODL can provide a maximum delay time of 150 ps with a resolution of 10 ps and feature a maximum insertion loss of 3.4 dB.展开更多
Photonics integration of an optoelectronic oscillator(OEO)on a chip is attractive for fabricating low cost,compact,low power consumption,and highly reliable microwave sources,which has been demonstrated recently in si...Photonics integration of an optoelectronic oscillator(OEO)on a chip is attractive for fabricating low cost,compact,low power consumption,and highly reliable microwave sources,which has been demonstrated recently in silicon on insulator(SOI)and indium phosphide(InP)platforms at X-band around 8 GHz.Here we demonstrate the first integration of OEOs on the thin film lithium niobate(TFLN)platform,which has the advantages of lower Vπ,no chirp,wider frequency range,and less sensitivity to temperature.We have successfully realized two different OEOs operating at Ka-band,with phase noises even lower than those of the X-band OEOs on SOI and InP platforms.One is a fixed frequency OEO at 30 GHz realized by integrating a Mach–Zehnder modulator(MZM)with an add-drop microring resonator(MRR),and the other is a tunable frequency OEO at 20–35 GHz realized by integrating a phase modulator(PM)with a notch MRR.Our work marks the first step of using TFLN to fabricate integrated OEOs with high frequency,small size,low cost,wide range tunability,and potentially low phase noise.展开更多
An integrated on-chip optical device consisting of two distributed feedback(DFB)lasers and one multimode semiconductor ring laser(SRL)has been numerically investigated.In this optical circuit,the two DFB lasers are in...An integrated on-chip optical device consisting of two distributed feedback(DFB)lasers and one multimode semiconductor ring laser(SRL)has been numerically investigated.In this optical circuit,the two DFB lasers are injected into the SRL,and with the presence of the four-wave mixing effect and optical feedback,the three semiconductor lasers achieve mutual-locking state.The beating between the output optical spectral lines can generate readily tunable radio frequency signals with high spectral purity.展开更多
Periodically poled lithium niobate on insulator(LNOI) ridge waveguides are desirable for high-efficiency nonlinear frequency conversions, and the fabrication process of such waveguides is crucial for device performanc...Periodically poled lithium niobate on insulator(LNOI) ridge waveguides are desirable for high-efficiency nonlinear frequency conversions, and the fabrication process of such waveguides is crucial for device performance. In this work, we report fabrication and characterization of locally periodically poled ridge waveguides. Ridge waveguides were fabricated by dry etching, and then the high-voltage pulses were applied to locally poled ridge waveguides. Second harmonic generation with normalized conversion efficiency of 435.5% W^(-1)·cm^(-2) was obtained in the periodically poled LNOI ridge waveguide,which was consistent with the triangular domain structure revealed by confocal microscopy.展开更多
Quantum-dot mode-locked lasers have advantages such as high temperature stability,large optical bandwidth,and low power consumption,which make them ideal optical comb sources,especially for wavelength-division multipl...Quantum-dot mode-locked lasers have advantages such as high temperature stability,large optical bandwidth,and low power consumption,which make them ideal optical comb sources,especially for wavelength-division multiplexing(WDM)telecommunications,and optical I/O applications.In this work,we demonstrate an O-band quantum dot colliding pulse mode-locked laser(QD-CPML)to generate optical frequency combs with 200 GHz spacing with maximum channels of 12 within 3 dB optical bandwidth.To achieve the high output power of individual comb lines,four channel conditions are implemented at central wavelength of 1310 nm for WDM transmission experiments.Each channel exhibits more than 10 dBm output power with 200 Gb/s PAM-4 and 270 Gb/s PAM-8 modulation capability via thin-film LiNbO_(3) Mach–Zehnder interferometer modulator without the requirement of any optical amplifications.This high-order QD-CPML is an ideal comb source for power-efficient optical interconnects and large bandwidth optical data transmission.展开更多
Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality....Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality. This paper reviews the state-of-the art in the field of OAM of light, reports recent developments in silicon integrated OAM emitters, and discusses the applications potentials and challenges in silicon integrated OAM devices which can be used in future OAM based optical communications systems.展开更多
In this paper, we proposed and experimentally demonstrated a route-asymmetrical light transmission scheme based on the thermal radiative effect, which means that forward and backward propagations of an optical device ...In this paper, we proposed and experimentally demonstrated a route-asymmetrical light transmission scheme based on the thermal radiative effect, which means that forward and backward propagations of an optical device have different transmittances provided they are not present simultaneously. Employing a fiber-chipfiber optomechanical system, our scheme has successfully achieved a broad operation bandwidth of at least 24 nm and an ultra-high route-asymmetrical transmission ratio （RATR） up to 63 dB. The route-asymmetrical device has been demonstrated effectively with not only the continuous-wave （CW） light but also 10 Gbit/s on-off-keying （OOK） digital signals. Above mentioned unique features can be mostly attributed to the significant characteristics of the thermal radiative effect, which could cause a fiber displacement up to tens of microns. The powerful and significant thermal radiative effect opens up a new opportunity and method for route-asymmetrical light transmission. Moreover, this research may have important applications in all-optical systems, such as the optical limiters and ultra-low loss switches.展开更多
Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quant...Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quantum level corresponds to photon spin or orbital angular momenta. OVs have attracted the attention of researchers in many areas of optics and photonics, as their potential applications range from optical communications, optical manipulation, imaging, sensing, to quantum information. In recent years, integrated photonics has becomes an effective method of manipulating OVs. In this paper, the theoretical framework and experimental progress of integrated photonics for the manipulation of OVs were reviewed.展开更多
文摘Why integratingⅢ–Ⅴsemiconductor on silicon Photonics is an enabling technology and play a significant role in today’s information age.In the last few decades,starting from the fiber long haul optical communications,optical interconnects have gradually replaced copper interconnects due to its advantage of the bandwidth distance product.As photonics is moving closer and closer to the processor and memory of computers,and eventually,to on-chip level,silicon photonics becomes a viable solution for future optical interconnections due to the feasibility of high-bandwidth,high-density I/O capability and dense integration enabled by the high index contrast.
基金sponsored by the National Key R&D Program of China(Grant No.2019YFA0705000)the National Natural Science Foundation of China(Grant Nos.11690031 and 11761131001).
文摘Thin-film lithium niobate is a promising material platform for integrated nonlinear photonics,due to its high refractive index contrast with the excellent optical properties.However,the high refractive index contrast and correspondingly small mode field diameter limit the attainable coupling between the waveguide and fiber.In second harmonic generation processes,lack of efficient fiber-chip coupling schemes covering both the fundamental and second harmonic wavelengths has greatly limited the overall efficiency.We design and fabricate an ultra-broadband tri-layer edge coupler with a high coupling efficiency.The coupler allows efficient coupling of 1 dB∕facet at 1550 nm and 3 dB∕facet at 775 nm.This enables us to achieve an ultrahigh overall second harmonic generation normalized efficiency(fiber-to-fiber)of 1027%W^(−1)cm^(−2)(on-chip second harmonic efficiency∼3256%W^(−1)cm^(−2))in a 5-mm-long periodically-poled lithium niobate waveguide,which is two to three orders of magnitude higher than that in state-of-the-art devices.
基金Natural Science Foundation of Hebei Province(F2024201002)Interdisciplinary Research Program of Natural Science of Hebei University(DXK202204)Research Start-up Foundation of High-Level Talents Introduction(8012605)。
文摘Linearly chirped microwave waveforms(LCMWs)are indispensable in advanced radar systems.Our study introduces and validates,through extensive experimentation,the innovative application of a thin-film lithium niobate(TFLN)photonic integrated circuit(PIC)to realize a Fourier domain mode-locked optoelectronic oscillator(FDML OEO)for generating high-precision LCMW signals.This integrated chip combines a phase modulator(PM)and an electrically tuned notch micro-ring resonator(MRR),which functions as a rapidly tunable bandpass filter,facilitating the essential phase-to-intensity modulation(PM-IM)conversion for OEO oscillation.By synchronizing the modulation period of the applied driving voltage to the MRR with the OEO loop delay,we achieve Fourier domain mode-locking,producing LCMW signals with an impressive tunable center frequency range of18.55 GHz to 23.59 GHz,an adjustable sweep bandwidth from 3.85 GHz to 8.5 GHz,and a remarkable chirp rate up to 3.22 GHz/μs.Unlike conventional PM-IM based FDML OEOs,our device obviates the need for expensive tunable lasers or microwave sources,positioning it as a practical solution for generating high-frequency LCMW signals with extended sweep bandwidth and high chirp rates,all within a compact and cost-efficient form factor.
基金National Natural Science Foundation of China(62405383)Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515110666)+2 种基金Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2021ZT09X044)Innovation Program for Quantum Science and Technology(2021ZD0301500)Innovation Program for Quantum Science and Technology(2021ZD0300700)。
文摘High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonlinearity of modulator materials,the complexity of external control devices,the bulkiness of structures,and bandwidth limitations.In this study,we present an integrated thin-film lithium niobate(TFLN)linear Mach–Zehnder modulator(LMZM),showing,to our knowledge,a record-high spurious-free dynamic range(SFDR)of 121.7 dB·Hz^(4∕5)at 1 GHz with an optical power(OP)of 5.5 dBm into the photodetector(PD),based on a widebandwidth(>50 GHz)dual-optical-mode(TE0 and TE1)co-modulated configuration with just one RF input.Additionally,compared to conventional MZMs(CMZMs),the LMZM exhibits a>10.6-dB enhancement in SFDR with an OP of>−8 dBm at 1 GHz,and maintains a 6.07-dB SFDR improvement even at 20 GHz with an OP of 0 dBm.The novel LMZM,featuring high linearity,wide bandwidth,structural simplicity,and high integration,holds significant potential as a key component in future large-scale and high-performance MWP integrated circuits.
基金supported by the National Natural Science Foundation of China(Nos.62335019 and 61975243)。
文摘Integrated optoelectronic chips working in the visible spectrum range have promising applications in augmented reality and virtual reality,quantum information processing,biosensors,and more.A silicon nitride optical phased array(OPA)can shape and steer light to enable these applications on a compact chip without moving parts.However,smaller wavelength,waveguide size,and the thermo-optic coefficient pose challenges in processing,calibration,and control of silicon nitride OPA chips.In this work,a high-speed phase control system for 532 nm silicon nitride OPA,utilizing a field programmable gate array and a digital-to-analog converter,achieves a 7.4μs voltage configuration.With this system,the single-shot multivoltage optimization of beam calibration of the OPA for tens of milliseconds is realized,and the beam scanning in the range of ±24° is demonstrated.The system fully meets the needs of high-speed scanning of silicon nitride OPA,advancing OPA's development and applications.
基金supported by the National Key Research and Development Program of China(2019YFB1803900 and 2019YFA0705000)National Natural Science Foundation of China(11690031 and 11761131001)+2 种基金Key R&D Program of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Key-Area Research and Development Program of Guangdong Province(2019B121204003).
文摘High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.
基金partially supported by the National Key R&D Program of China(Nos.2019YFA0705000 and 2019YFB1803900)the National Natural Science Foundation of China(Nos.11690031 and 11761131001)+3 种基金the Key R&D Program of Guangdong Province(No.2018B030329001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01X121)the Innovation Fund of WNLO(No.2018WNLOKF010)the Project of Key Laboratory of Radar Imaging and Microwave Photonics,Ministry of Education(No.RIMP2019003)。
文摘Integrated traveling-wave lithium niobate modulators need relatively large device lengths to achieve low drive voltage. To increase modulation efficiency within a compact footprint, we report an integrated Fabry–Perot-type electro-optic thin film lithium niobate on insulator modulator comprising a phase modulation region sandwiched between two distributed Bragg reflectors. The device exhibits low optical loss and a high tuning efficiency of 15.7 pm/V. We also confirm the modulator's high-speed modulation performance by non-return-to-zero modulation with a data rate up to 56 Gbit/s.
基金National Key R&D Programme of China(2019YFA0706300,2018YFB1801800)NSFC-Guangdong joint programme(U2001601)+3 种基金National Natural Science Foundation of China(61875233,62101602)The Key R&D Programme of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Programme(2017BT01X121)the Fundamental Research Funds for the Central Universities(22lgqb16).
文摘Space-division multiplexing(SDM),as a main candidate for future ultra-high capacity fibre-optic communications,needs to address limitations to its scalability imposed by computation-intensive multi-input multi-output(MIMO)digital signal processing(DSP)required to eliminate the crosstalk caused by optical coupling between multiplexed spatial channels.By exploiting the unique propagation characteristics of orbital angular momentum(OAM)modes in ring core fibres(RCFs),a system that combines SDM and C+L band dense wavelength-division multiplexing(DWDM)in a 34 km 7-core RCF is demonstrated to transport a total of 24960 channels with a raw(net)capacity of 1.223(1.02)Peta-bit s−1(Pbps)and a spectral efficiency of 156.8(130.7)bit s−1 Hz−1.Remarkably for such a high channel count,the system only uses fixed-size 4×4 MIMO DSP modules with no more than 25 time-domain taps.Such ultra-low MIMO complexity is enabled by the simultaneous weak coupling among fibre cores and amongst non-degenerate OAM mode groups within each core that have a fixed number of 4 modes.These results take the capacity of OAM-based fibre-optic communications links over the 1 Pbps milestone for the first time.They also simultaneously represent the lowest MIMO complexity and the 2nd smallest fibre cladding diameter amongst reported few-mode multicore-fibre(FM-MCF)SDM systems of>1 Pbps capacity.We believe these results represent a major step forward in SDM transmission,as they manifest the significant potentials for further up-scaling the capacity per optical fibre whilst keeping MIMO processing to an ultra-low complexity level and in a modularly expandable fashion.
基金National Key Research and Development Program of China(2019YFB1803900)National Natural Science Foundation of China(11690031,11761131001)+6 种基金Guangzhou Science and Technology Program(201707010096)Key RD Program of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Innovation Fund of WNLO(2018WNLOKF010)Key-Area Research and Development Program of Guangdong Province(2019B121204003)Project of Key Laboratory of Radar Imaging and Microwave Photonics,Ministry of Education(RIMP2019003)Opening funds from State Key Laboratory of Optoelectronic Materials and Technologies of China,Sun Yat-sen University(OEMT-2018-KF-04)。
文摘Optical modulators have been and will continue to be essential devices for energy-and cost-efficient optical communication networks.Heterogeneous silicon and lithium niobate modulators have demonstrated promising performances of low optical loss,low drive voltage,and large modulation bandwidth.However,DC bias drift is a major drawback of optical modulators using lithium niobate as the active electro-optic material.Here,we demonstrate high-speed and bias-drift-free Mach–Zehnder modulators based on the heterogeneous silicon and lithium niobate platform.The devices combine stable thermo-optic DC biases in silicon and ultra-fast electro-optic modulation in lithium niobate,and exhibit a low insertion loss of 1.8 d B,a low half-wave voltage of 3 V,an electro-optic modulation bandwidth of at least 70 GHz,and modulation data rates up to 128 Gb/s.
基金supported by the National Key Research and Development Program of China(Nos.2017YFA0303704,2019YFA0308700,and 2017YFA0304002)the National Natural Science Foundation of China(Nos.11690032,11321063,and 12033002)+2 种基金the NSFC-BRICS(No.61961146001)the Leading-Edge Technology Program of Jiangsu Natural Science Foundation(No.BK20192001)the Fundamental Research Funds for the Central Universities.
文摘Integrated photonics provides a route to both miniaturization of quantum key distribution(QKD)devices and enhancing their performance.A key element for achieving discrete-variable QKD is a singlephoton detector.It is highly desirable to integrate detectors onto a photonic chip to enable the realization of practical and scalable quantum networks.We realize a heterogeneously integrated,superconducting silicon-photonic chip.Harnessing the unique high-speed feature of our optical waveguide-integrated superconducting detector,we perform the first optimal Bell-state measurement(BSM)of time-bin encoded qubits generated from two independent lasers.The optimal BSM enables an increased key rate of measurement-device-independent QKD(MDI-QKD),which is immune to all attacks against the detection system and hence provides the basis for a QKD network with untrusted relays.Together with the timemultiplexed technique,we have enhanced the sifted key rate by almost one order of magnitude.With a 125-MHz clock rate,we obtain a secure key rate of 6.166 kbps over 24.0 dB loss,which is comparable to the state-of-the-art MDI-QKD experimental results with a GHz clock rate.Combined with integrated QKD transmitters,a scalable,chip-based,and cost-effective QKD network should become realizable in the near future.
基金supported by the National Key R&D Program of China(No.2019YFA0705000)Key R&D Program of Guangdong Province(No.2018B030329001)+2 种基金Leading-edge Technology Program of Jiangsu Natural Science Foundation(No.BK20192001)National Natural Science Foundation of China(Nos.51890861,11690031,11674169,91950206,and 11974178)Fundamental Research Funds for the Central Universities(No.021314380177)。
文摘We study the effect of dimension variation for second-harmonic generation(SHG) in lithium niobate on insulator(LNOI)waveguides. Non-trivial SHG profiles in both type-0 and type-I quasi-phase matching are observed during the wavelength tuning of the fundamental light. Theoretical modeling shows that the SHG profile and efficiency can be greatly affected by the waveguide cross-section dimension variations, especially the thickness variations. In particular, our analysis shows that a thickness variation of tens of nanometers is in good agreement with the experimental results. Such investigations could be used to evaluate fabrication performance of LNOI-based nonlinear optical devices.
基金supported in part by the National Key R&D Program of China(Nos.2019YFB1803900 and 2019YFA0705000)the National Natural Science Foundation of China(Nos.11690031,11761131001,and 11904061)+6 种基金the Key R&D Program of Guangdong Province(No.2018B030329001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01X121)the Project of Key Laboratory of Radar Imaging and Microwave Photonics,Ministry of Education(No.RIMP2019003)the Innovation Fund of WNLO(No.2018WNLOKF010),the Guangzhou Science and Technology Program(No.201707010096)the Guangxi Youth and Middle Aged Ability Promotion Project(No.2019KY0126)the BaGui Scholar Programof Guangxi Province(No.02304002022C)the China Postdoctoral Science Foundation(No.2020M673554XB).
文摘We propose and demonstrate a polarization diversity two-dimensional grating coupler based on the lithium niobate on insulator platform, for the first time, to the best of our knowledge. The optimization design, performance characteristics,and fabrication tolerance of the two-dimensional grating coupler are thoroughly analyzed utilizing the three-dimensional finite-difference time-domain method. Experimentally,-7.2 d B of coupling efficiency is achieved with 1 d B bandwidth of64 nm. The polarization-dependent loss is about 0.4 d B around 1550 nm. Our work provides new polarization multiplexing approaches for the lithium niobate on insulator platform, paving the way for critical applications such as high-speed polarization multiplexed electro-optical modulators.
基金National Key Research and Development Program of China(2019YFA0705004,2019YFB1803901)Key R&D Program of Guangdong Province(2018B03032900)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)。
文摘A tunable optical delay line(ODL) featuring high switching speed and low optical loss is highly desirable in many fields. Here, based on the thin-film lithium niobate platform, we demonstrate a digitally tunable on-chip ODL that includes five Mach–Zehnder interferometer optical switches, four flip-chip photodetectors, and four delayline waveguides. The proposed optical switches can achieve a switching speed of 13 ns and an extinction ratio of34.9 dB. Using a modified Euler-bend-based spiral structure, the proposed delay-line waveguide can simultaneously achieve a small footprint and low optical propagation loss. The proposed ODL can provide a maximum delay time of 150 ps with a resolution of 10 ps and feature a maximum insertion loss of 3.4 dB.
基金National Key Research and Development Program of China(2019YFA0705000)National Natural Science Foundation of China(62293523)+1 种基金Advanced Talents Program of Hebei University(521000981006)Natural Science Foundation of Hebei Province(F2021201013).
文摘Photonics integration of an optoelectronic oscillator(OEO)on a chip is attractive for fabricating low cost,compact,low power consumption,and highly reliable microwave sources,which has been demonstrated recently in silicon on insulator(SOI)and indium phosphide(InP)platforms at X-band around 8 GHz.Here we demonstrate the first integration of OEOs on the thin film lithium niobate(TFLN)platform,which has the advantages of lower Vπ,no chirp,wider frequency range,and less sensitivity to temperature.We have successfully realized two different OEOs operating at Ka-band,with phase noises even lower than those of the X-band OEOs on SOI and InP platforms.One is a fixed frequency OEO at 30 GHz realized by integrating a Mach–Zehnder modulator(MZM)with an add-drop microring resonator(MRR),and the other is a tunable frequency OEO at 20–35 GHz realized by integrating a phase modulator(PM)with a notch MRR.Our work marks the first step of using TFLN to fabricate integrated OEOs with high frequency,small size,low cost,wide range tunability,and potentially low phase noise.
基金by the 973 program of the Chinese Ministry of Science and Technology,under Project No.2012CB315702.
文摘An integrated on-chip optical device consisting of two distributed feedback(DFB)lasers and one multimode semiconductor ring laser(SRL)has been numerically investigated.In this optical circuit,the two DFB lasers are injected into the SRL,and with the presence of the four-wave mixing effect and optical feedback,the three semiconductor lasers achieve mutual-locking state.The beating between the output optical spectral lines can generate readily tunable radio frequency signals with high spectral purity.
基金supported by the National Key R&D Program of China(Nos.2019YFA0705000 and 2017YFA0303700)the National Natural Science Foundation of China(Nos.91950206,11627810,and 51890861)+2 种基金the Leading-edge Technology Program of Jiangsu Natural Science Foundation(No.BK20192001)the Key R&D Program of Guangdong Province(No.2018B030329001)the Fundamental Research Funds for the Central Universities(No.021314380177)。
文摘Periodically poled lithium niobate on insulator(LNOI) ridge waveguides are desirable for high-efficiency nonlinear frequency conversions, and the fabrication process of such waveguides is crucial for device performance. In this work, we report fabrication and characterization of locally periodically poled ridge waveguides. Ridge waveguides were fabricated by dry etching, and then the high-voltage pulses were applied to locally poled ridge waveguides. Second harmonic generation with normalized conversion efficiency of 435.5% W^(-1)·cm^(-2) was obtained in the periodically poled LNOI ridge waveguide,which was consistent with the triangular domain structure revealed by confocal microscopy.
基金National Key Research and Development Program of China(2021YFB2800403)National Natural Science Foundation of China(12274449,62005308,62225407,62334013)+2 种基金Innovation Program for Quantum Science and Technology(2021ZD0302300)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y2022005)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2023008).
文摘Quantum-dot mode-locked lasers have advantages such as high temperature stability,large optical bandwidth,and low power consumption,which make them ideal optical comb sources,especially for wavelength-division multiplexing(WDM)telecommunications,and optical I/O applications.In this work,we demonstrate an O-band quantum dot colliding pulse mode-locked laser(QD-CPML)to generate optical frequency combs with 200 GHz spacing with maximum channels of 12 within 3 dB optical bandwidth.To achieve the high output power of individual comb lines,four channel conditions are implemented at central wavelength of 1310 nm for WDM transmission experiments.Each channel exhibits more than 10 dBm output power with 200 Gb/s PAM-4 and 270 Gb/s PAM-8 modulation capability via thin-film LiNbO_(3) Mach–Zehnder interferometer modulator without the requirement of any optical amplifications.This high-order QD-CPML is an ideal comb source for power-efficient optical interconnects and large bandwidth optical data transmission.
文摘Emerging applications based on optical beams carrying orbital angular momentum （OAM） will likely require photonic integrated devices and circuits for miniaturization, improved performance and enhanced functionality. This paper reviews the state-of-the art in the field of OAM of light, reports recent developments in silicon integrated OAM emitters, and discusses the applications potentials and challenges in silicon integrated OAM devices which can be used in future OAM based optical communications systems.
基金Acknowledgements This work was partially supported by the National Basic Research Program of China （No. 2011CB301704）, the Program for New Century Excellent Talents in Ministry of Education of China （No. NCET-11-0168）, a Foundation for the Author of National Excellent Doctoral Dissertation of China （No. 201139）, the National Natural Science Foundation of China （Grant Nos. 11174096 and 61475052）, and the Opened Fund of the State Key Laboratory on Advanced Optical Communication System and Network （No. 2015GZKF03004）.
文摘In this paper, we proposed and experimentally demonstrated a route-asymmetrical light transmission scheme based on the thermal radiative effect, which means that forward and backward propagations of an optical device have different transmittances provided they are not present simultaneously. Employing a fiber-chipfiber optomechanical system, our scheme has successfully achieved a broad operation bandwidth of at least 24 nm and an ultra-high route-asymmetrical transmission ratio （RATR） up to 63 dB. The route-asymmetrical device has been demonstrated effectively with not only the continuous-wave （CW） light but also 10 Gbit/s on-off-keying （OOK） digital signals. Above mentioned unique features can be mostly attributed to the significant characteristics of the thermal radiative effect, which could cause a fiber displacement up to tens of microns. The powerful and significant thermal radiative effect opens up a new opportunity and method for route-asymmetrical light transmission. Moreover, this research may have important applications in all-optical systems, such as the optical limiters and ultra-low loss switches.
基金The authors wish to acknowledge support by the National Basic Research Program of China （No. 2014CB340000）, the National Natural Science Foundation of China-Key Research Project （Grant No. 61490715）, and the EU Horizon2020 program under project ROAM.
文摘Optical vortices （OVs） refer to a class of cylindrical optical modes with azimuthally varying phase terms arising either from polarization rotation or from the angular projection of the wave vector that at the quantum level corresponds to photon spin or orbital angular momenta. OVs have attracted the attention of researchers in many areas of optics and photonics, as their potential applications range from optical communications, optical manipulation, imaging, sensing, to quantum information. In recent years, integrated photonics has becomes an effective method of manipulating OVs. In this paper, the theoretical framework and experimental progress of integrated photonics for the manipulation of OVs were reviewed.
