Ultrashort pulses complicate the frequency conversion in a nonlinear crystal, where group velocity mismatch becomes the main obstacle due to dispersion. We present a design for group velocity compensated second harmon...Ultrashort pulses complicate the frequency conversion in a nonlinear crystal, where group velocity mismatch becomes the main obstacle due to dispersion. We present a design for group velocity compensated second harmonic generation in a modulated nonlinear structure, embedded in a liquid crystal box. In this structure, nonlinear crystals act as sources of signal and liquid crystals compensate for group velocity mismatch originating from nonlinear crystals. There are the advantages of the flexible, controllable birefringence of liquid crystals. Meanwhile, a method calculating the parameters of this type of structure is presented. To make it clear, an example is provided. Furthermore, the structure can also be shaped as a waveguide to support integration into other optical devices, applicable to all-optical processing systems.展开更多
Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely e...Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely employed in various fields,including optical communication,sensing,and filtering.In this study,we investigate the modification mechanisms associated with femtosecond laser interactions with MRRs fabricated on a lowpressure chemical vapor deposition(LPCVD)-silicon nitride(SiN)photonic platform,with emphasis on the post-fabrication trimming of second-order microring filters and MRR-based four-channel wavelength-division multiplexing(WDM).We examine 10 MRRs located at different positions on a wafer and discovered resonance wavelength shifts exceeding 1 nm due to fabrication-induced variations.Interactions between femtosecond lasers and LPCVD-SiN films resulted in silicon nanoclusters,which significantly redshifted the resonance wavelength of the MRRs.Additionally,the extinction ratio of MRRs improved by over 11.8 dB within the conventional band after laser modification.This technique is employed to enhance the performance of second-order MRRs and the four-channel WDM configuration,thus providing critical experimental evidence for leveraging femtosecond lasers to optimize LPCVD-SiN PICs.展开更多
Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments ...Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments and big data communication.Femtosecond(fs)laser direct writing(FLDW)is an acknowledged technique for producing waveguides(WGs)in transparent glass that have been used to construct complex integrated photonic devices.FLDW possesses unique features,such as three-dimensional fabrication geometry,rapid prototyping,and single step fabrication,which are important for integrated communication devices and quantum photonic and astrophotonic technologies.To fully take advantage of FLDW,considerable efforts have been made to produce WGs over a large depth with low propagation loss,coupling loss,bend loss,and highly symmetrical mode field.We summarize the improved techniques as well as the mechanisms for writing high-performance WGs with controllable morphology of cross-section,highly symmetrical mode field,low loss,and high processing uniformity and efficiency,and discuss the recent progress of WGs in photonic integrated devices for communication,topological physics,quantum information processing,and astrophotonics.Prospective challenges and future research directions in this field are also pointed out.展开更多
We review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optica...We review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optical interconnects, we propose a wavelength-division-multiplexing(WDM)-based optical interconnect for intra-datacenter applications. Following our proposed interconnects configuration, the bulk of the review emphasizes recent developments concerning on-chip hybrid silicon microlasers and WDM transmitters, and silicon photonic switch fabrics for intra-datacenters. For hybrid silicon microlasers and WDM transmitters, we outline the remaining challenges and key issues toward realizing low power consumption, direct modulation, and integration of multiwavelength microlaser arrays. For silicon photonic switch fabrics, we review various topologies and configurations of high-port-count N-by-N switch fabrics using Mach–Zehnder interferometers and microring resonators as switch elements, and discuss their prospects toward practical implementations with active reconfiguration.For the microring-based switch fabrics, we review recent developments of active stabilization schemes at the subsystem level. Last, we outline several large challenges and problems for silicon and hybrid silicon photonics to meet for intra-datacenter applications and propose potential solutions.展开更多
We review current silicon photonic devices and their performance in connection with energy consumption.Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of ...We review current silicon photonic devices and their performance in connection with energy consumption.Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy performance of modulators, and enhancing the sensitivity of photodetectors. Major conclusions are(1) Mach–Zehnder interferometer-based devices can achieve athermal performance without any extra energy consumption while microrings do not have an efficient passive athermal solution;(2) while direct bonded III–V-based Si lasers can meet system power requirement for now, hetero-epitaxial grown III–V quantum dot lasers are competitive and may be a better option for the future;(3) resonant modulators, especially coupling modulators, are promising for low-energy consumption operation even when the power to stabilize their operation is included;(4) benefiting from high sensitivity and low cost, Ge/Si avalanche photodiode is the most promising photodetector and can be used to effectively reduce the optical link power budget. These analyses and solutions will contribute to further lowering energy consumption to meet aggressive energy demands in future systems.展开更多
Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to p...Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.展开更多
Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose...Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose significant limitations on capacity expansion,often requiring physical replacement and causing service disruptions.Thermally tunable optical splitters address this challenge by enabling adjustable splitting ratios,but their operation is contingent upon a continuous power supply and complex driving systems.In this work,we present a novel,non-volatile tunable PLC platform based on Sb_(2)S_(3)phase-change materials.The proposed device,which incor-porates a Mach-Zehnder interferometer(MZI)optical switch structure,offers tunable splitting ratios via laser-direct writing or ohmic heating,providing flexible reconfiguration capabilities.Experimental results demonstrate non-volatile power splitting ranging from 50∶50 to 20∶80,with a modest increase of approximately 1 dB in additional loss.This work highlights the potential of the proposed platform for low-power,high-efficiency,and reconfigurable photonic networks.展开更多
Graphene-lithium niobate(G-LN)integration has emerged as a promising approach for advancing acoustoelectric,photonic,and optic devices.This hybrid integration leverages graphene’s remarkable optical transparency,exce...Graphene-lithium niobate(G-LN)integration has emerged as a promising approach for advancing acoustoelectric,photonic,and optic devices.This hybrid integration leverages graphene’s remarkable optical transparency,excellent conductivity,high carrier mobility,tunable electronic properties,and compatibility with complementary metal oxide semiconductor technology,alongside LN’s high electro-optic,acousto-optic,and nonlinearoptic coefficients,creating a highly functional platform for novel devices.This mini-review comprehensively synthesizes the state-of-the-art and recent advancements in G-LN integration,summarizing its fundamental principles and processes of practical fabrication techniques,and exploring surface acoustic waves,graphene electrodes,surface plasmon polaritons,and graphene absorbers.This mini-review of G-LN integration could underscore its significance in supporting more robust,energy-efficient,high-performance,and uniquely diverse devices,implying its potential to drive breakthroughs across multiple disciplines,as well as inspire further advancements in G-LN integration-based device design and applications.展开更多
We investigate nonreciprocal transmission in microcavity exciton polaritons and obtain analytical conditions for achieving unidirectional and circular transmission.The phase difference between two effective optomechan...We investigate nonreciprocal transmission in microcavity exciton polaritons and obtain analytical conditions for achieving unidirectional and circular transmission.The phase difference between two effective optomechanical couplings can regulate the interference of different channels between two photon modes,and control the direction of nonreciprocity,resulting in unidirectional forward and backward transmissions.Perfect nonreciprocal unidirectional transmission with zero losses is realized,which depends on exciton-photon-phonon couplings.Moreover,clockwise and counterclockwise circular transmissions are implemented by appropriately adjusting the phase of photon mode couplings.Our results open up exciting possibilities for implementing nonreciprocal photonic devices.展开更多
Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established base...Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.展开更多
Nd3＋,Eu3＋ and Tb3＋ ions doped transparent chlorophosphate glass ceramics were prepared and their frequency-conversion properties were studied. X-ray diffraction （XRD） patterns evidenced the formation of expected ...Nd3＋,Eu3＋ and Tb3＋ ions doped transparent chlorophosphate glass ceramics were prepared and their frequency-conversion properties were studied. X-ray diffraction （XRD） patterns evidenced the formation of expected halide nanocrystals. The absorption,excitation and emission spectra investigation indicated that some of rare earth （RE） ions were trapped in low phonon energy halide nanocrystals,and therefore an efficient down frequency-conversion was observed. The comparative spectroscopic studies of RE doped samples suggested that the glass ceramics systems are potentially applicable as efficient ultraviolet to visible frequency-conversion photonics materials.展开更多
Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them...Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.展开更多
Systemic blood circulation is one of life activity’s most important physiological functions.Continuous noninvasive hemodynamicmonitoring is essential for the management of cardiovascular status.However,it is difficul...Systemic blood circulation is one of life activity’s most important physiological functions.Continuous noninvasive hemodynamicmonitoring is essential for the management of cardiovascular status.However,it is difficult to achieve systemichemodynamic monitoring with the daily use of current devices due to the lack of multichannel and time-synchronized operationcapability over the whole body.Here,we utilize a soft microfiber Bragg grating group to monitor spatiotemporalhemodynamics by taking advantage of the high sensitivity,electromagnetic immunity,and great temporal synchronizationbetween multiple remote sensor nodes.A continuous systemic hemodynamic measurement technique is developedusing all-mechanical physiological signals,such as ballistocardiogram signals and pulse waves,to illustrate the actualmechanical process of blood circulation.Multiple hemodynamic parameters,such as systemic pulse transit time,heartrate,blood pressure,and peripheral resistance,are monitored using skin-like microfiber Bragg grating patches conformallyattached at different body locations.Relying on the soft microfiber Bragg grating group,the spatiotemporal hemodynamicmonitoring technique opens up new possibilities in clinical medical diagnosis and daily health management.展开更多
The passive radiative cooling technology shows a great potential application on reducing the enormous global energy consumption.The multilayer metamaterials could enhance the radiative cooling performance.However,it i...The passive radiative cooling technology shows a great potential application on reducing the enormous global energy consumption.The multilayer metamaterials could enhance the radiative cooling performance.However,it is a challenge to design the radiative cooler.In this work,based on the particle swarm optimization(PSO)evolutionary algorithm,we develop an intelligent workflow in designing photonic radiative cooling metamaterials.Specifically,we design two 10-layer SiO_(2) radiative coolers doped by cylindrical MgF_(2) or air impurities,possessing high emissivity within the selective(8–13μm)and broadband(8–25μm)atmospheric transparency windows,respectively.Our two kinds of coolers demonstrate power density as high as 119 W/m^(2) and 132 W/m^(2) at the room temperature(300 K).Our scheme does not rely on the usage of special materials,forming high-performing metamaterials with conventional poor-performing components.This significant improvement of the emission spectra proves the effectiveness of our inverse design algorithm in boosting the discovery of high-performing functional metamaterials.展开更多
Optical mode converters are essential for enhancing the capacity of optical communication systems. However, fabrication errors restrict the further improvement of conventional mode converters. To address this challeng...Optical mode converters are essential for enhancing the capacity of optical communication systems. However, fabrication errors restrict the further improvement of conventional mode converters. To address this challenge, we have designed an on-chip TE0–TE1mode converter based on topologically protected waveguide arrays. The simulation results demonstrate that the converter exhibits a mode coupling efficiency of 93.5% near 1550 nm and can tolerate a relative fabrication error of 30%. Our design approach can be extended to enhance the robustness for other integrated photonic devices, beneficial for future development of optical network systems.展开更多
A modified wide-angle beam propagation based on the Douglas operators is presented.The truncation error in the modified wide-angle beam propagation is reduced to o (Δ x ) 4 in the transverse direction nearly wi...A modified wide-angle beam propagation based on the Douglas operators is presented.The truncation error in the modified wide-angle beam propagation is reduced to o (Δ x ) 4 in the transverse direction nearly without any increase of the computation time,whereas the error in the ordinary wide-angle beam propagation method is typically o (Δ x ) 2.With trivial programming changes,the accuracy is higher,especially in wide-angle propagation.展开更多
The rapid advancement of renewable energy technologies is essential for combating global climate change and achieving energy sustainability.Among the various renewable sources,solar energy stands out,with silicon play...The rapid advancement of renewable energy technologies is essential for combating global climate change and achieving energy sustainability.Among the various renewable sources,solar energy stands out,with silicon playing a pivotal role in solar energy conversion.However,traditional silicon-based devices often face challenges due to high surface reflectance,which limits their efficiency.The emergence of black silicon(b-Si)offers a transformative solution,thanks to its micro-and nanoscale structures that provide ultra-low reflectivity and enhanced light absorption.This makes b-Si an ideal candidate for improving solar energy devices.Beyond solar energy applications,b-Si has drawn notable interest in photonics,including applications in photodetectors,surface-enhanced Raman scattering,and imaging.This review explores b-Si comprehensively,discussing its fabrication processes,distinctive properties,and contributions to both solar energy conversion and photonic technologies.Key topics include its roles in solar cells,photoelectrochemical systems,solar thermal energy conversion,and advanced photonic devices.Furthermore,the review addresses the challenges and future directions for optimizing b-Si to facilitate its practical deployment across a range of energy and photonic applications.展开更多
Reconfigurable silicon microrings have garnered significant interest for addressing challenges in artificial intelligence,the Internet of Things,and telecommunications due to their versatile capabilities.Compared to e...Reconfigurable silicon microrings have garnered significant interest for addressing challenges in artificial intelligence,the Internet of Things,and telecommunications due to their versatile capabilities.Compared to electrooptic(EO)and thermo-optic(TO)devices,emerging micro-electromechanical systems(MEMS)-based reconfigurable silicon photonic devices actuated by electrostatic forces offer near-zero static power consumption.This study proposes and implements novel designs for fully reconfigurable silicon photonic MEMS microrings for high-speed dense wavelength division multiplexing(DWDM)elastic networks.The designs include an all-pass microring with a 7 nm free spectral range(FSR)and full-FSR resonance tuning range,an add-drop microring with a 3.5 nm FSR and full-FSR tuning range,and an add-drop double-microring with a 34 nm FSR,wide-range discrete resonance tunability,and flat-top tunability.These advancements hold promise for practical applications.展开更多
The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focus...The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focusing ultrashort laser pulses into transparent optical materials,such as crystals and glasses,it is possible to efficiently modify specific optical properties,including refractive indices and ferroelectric domains,at the laser focus.By carefully designing and optimizing the movement trajectory of the femtosecond laser,one can achieve periodic modulation of the optical features of these materials in 3D space.The resulting changes in material properties are closely linked to both the processing parameters of the femtosecond laser and the types of materials used.Through ongoing optimization of these parameters,desired periodic photonic structures can be created in specific transparent optical materials,leading to the development of 3D nonlinear photonic crystals(NPCs)and 3D waveguide arrays.Femtosecond laser direct writing breaks through the limitations of traditional techniques to fabricate 3D NPCs[e.g.,3D lithium niobate(LiNbO_(3))NPCs]and complex waveguide arrays(e.g.,3D helical waveguide arrays),realizing a paradigm shift in the fabrication of complex periodic photonic structures.To date,femtosecond-laser-written 3D NPCs and waveguide arrays have found extensive applications in integrated photonics,nonlinear optics,quantum optics,and topological photonics.We highlight recent advancements in femtosecond-laser-written 3D NPCs and waveguide arrays,such as pivotal breakthroughs in the fabrication of nanoscale-resolution 3D NPCs in LiNbO_(3).Finally,several potential research directions,such as the formation mechanism of domain wall and inducing millimeter-scale domain inversion with femtosecond Bessel beam,have been proposed at the end of this article.展开更多
Meta-devices,known for their capability to manipulate light fields at a subwavelength scale,have gained significant traction in the realm of quantum photonics in recent years.They are being utilized in miniaturized ap...Meta-devices,known for their capability to manipulate light fields at a subwavelength scale,have gained significant traction in the realm of quantum photonics in recent years.They are being utilized in miniaturized applications such as the preparation of quantum light sources and the control and detection of quantum states.In this review,we provide a systematic explanation of the working principles and notable applications of metadevices in quantum optical information processing,while also outlining potential directions for the future development of quantum meta-devices.展开更多
基金Supported by the Natural Science Foundation of Heilongjiang Province under Grant Nos F201312,F2016023 and QC2015086the National Natural Science Foundation of China under Grant No 61405049
文摘Ultrashort pulses complicate the frequency conversion in a nonlinear crystal, where group velocity mismatch becomes the main obstacle due to dispersion. We present a design for group velocity compensated second harmonic generation in a modulated nonlinear structure, embedded in a liquid crystal box. In this structure, nonlinear crystals act as sources of signal and liquid crystals compensate for group velocity mismatch originating from nonlinear crystals. There are the advantages of the flexible, controllable birefringence of liquid crystals. Meanwhile, a method calculating the parameters of this type of structure is presented. To make it clear, an example is provided. Furthermore, the structure can also be shaped as a waveguide to support integration into other optical devices, applicable to all-optical processing systems.
基金National Natural Science Foundation of China(62375274)Key Deployment Project of Chinese Academy of Sciences(KGFZD-145-24-12)Shanghai Industrial Collaborative Innovation Project(XTCX-KJ-2023-01)。
文摘Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely employed in various fields,including optical communication,sensing,and filtering.In this study,we investigate the modification mechanisms associated with femtosecond laser interactions with MRRs fabricated on a lowpressure chemical vapor deposition(LPCVD)-silicon nitride(SiN)photonic platform,with emphasis on the post-fabrication trimming of second-order microring filters and MRR-based four-channel wavelength-division multiplexing(WDM).We examine 10 MRRs located at different positions on a wafer and discovered resonance wavelength shifts exceeding 1 nm due to fabrication-induced variations.Interactions between femtosecond lasers and LPCVD-SiN films resulted in silicon nanoclusters,which significantly redshifted the resonance wavelength of the MRRs.Additionally,the extinction ratio of MRRs improved by over 11.8 dB within the conventional band after laser modification.This technique is employed to enhance the performance of second-order MRRs and the four-channel WDM configuration,thus providing critical experimental evidence for leveraging femtosecond lasers to optimize LPCVD-SiN PICs.
基金This work was financially supported by the National Key R&D Program of China(2020YFB1805900)the National Natural Science Foundation of China(U20A20211,51902286,61775192,61905215,and 51772270)Open Funds of the State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,and the Fundamental Research Funds for the Central Universities.The authors declare no competing financial interest.
文摘Integrated photonics is attracting considerable attention and has found many applications in both classical and quantum optics,fulfilling the requirements for the ever-growing complexity in modern optical experiments and big data communication.Femtosecond(fs)laser direct writing(FLDW)is an acknowledged technique for producing waveguides(WGs)in transparent glass that have been used to construct complex integrated photonic devices.FLDW possesses unique features,such as three-dimensional fabrication geometry,rapid prototyping,and single step fabrication,which are important for integrated communication devices and quantum photonic and astrophotonic technologies.To fully take advantage of FLDW,considerable efforts have been made to produce WGs over a large depth with low propagation loss,coupling loss,bend loss,and highly symmetrical mode field.We summarize the improved techniques as well as the mechanisms for writing high-performance WGs with controllable morphology of cross-section,highly symmetrical mode field,low loss,and high processing uniformity and efficiency,and discuss the recent progress of WGs in photonic integrated devices for communication,topological physics,quantum information processing,and astrophotonics.Prospective challenges and future research directions in this field are also pointed out.
基金financial support from the National Science Foundation of China (NSFC)the Research Grants Council (RGC) of the Hong Kong Special Administrative Region (HKSAR) under project N_HKUST606/10+5 种基金the State Key Laboratory on Integrated Optoelectronics, ChinaOpen Fund of the State Key Laboratory on Integrated Optoelectronics under project IOSKL2013KF04the Innovation and Technology Fund (ITF) of the HKSAR under project ITS/023/14 and ITS/087/13the Proof-of-Concept Fund (PCF) of The Hong Kong University of Science and Technology (HKUST) under project no. PCF007.12/13the General Research Fund (GRF) of the HKSAR under project no. 16208114postdoctoral fellowship support from the Hong Kong Scholars Program 2013
文摘We review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optical interconnects, we propose a wavelength-division-multiplexing(WDM)-based optical interconnect for intra-datacenter applications. Following our proposed interconnects configuration, the bulk of the review emphasizes recent developments concerning on-chip hybrid silicon microlasers and WDM transmitters, and silicon photonic switch fabrics for intra-datacenters. For hybrid silicon microlasers and WDM transmitters, we outline the remaining challenges and key issues toward realizing low power consumption, direct modulation, and integration of multiwavelength microlaser arrays. For silicon photonic switch fabrics, we review various topologies and configurations of high-port-count N-by-N switch fabrics using Mach–Zehnder interferometers and microring resonators as switch elements, and discuss their prospects toward practical implementations with active reconfiguration.For the microring-based switch fabrics, we review recent developments of active stabilization schemes at the subsystem level. Last, we outline several large challenges and problems for silicon and hybrid silicon photonics to meet for intra-datacenter applications and propose potential solutions.
基金supported by the Major International Cooperation and Exchange Program of the National Natural Science Foundation of China under Grant 61120106012
文摘We review current silicon photonic devices and their performance in connection with energy consumption.Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy performance of modulators, and enhancing the sensitivity of photodetectors. Major conclusions are(1) Mach–Zehnder interferometer-based devices can achieve athermal performance without any extra energy consumption while microrings do not have an efficient passive athermal solution;(2) while direct bonded III–V-based Si lasers can meet system power requirement for now, hetero-epitaxial grown III–V quantum dot lasers are competitive and may be a better option for the future;(3) resonant modulators, especially coupling modulators, are promising for low-energy consumption operation even when the power to stabilize their operation is included;(4) benefiting from high sensitivity and low cost, Ge/Si avalanche photodiode is the most promising photodetector and can be used to effectively reduce the optical link power budget. These analyses and solutions will contribute to further lowering energy consumption to meet aggressive energy demands in future systems.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 11474108, 61378036, 61307058, 11304101, 11074078)the PhD Start-up Fund of Natural Science Foundation of Guangdong Province, China (Grant No. S2013040016320)+2 种基金the Scientific and Technological Innovation Project of Higher Education Institute, Guangdong, China (Grant No. 2013KJCX0051)the financial support from the Guangdong Natural Science Funds for Distinguished Young Scholarthe Zhujiang New-star Plan of Science & Technology in Guangzhou City (Grant No. 2014J2200008)
文摘Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.
基金sponsored by the National Key Research and Development Program of China(2020YFA0714504,2019YFA0709100)the program of the National Natural Science Foundation of China(U24A20309,62305043).
文摘Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose significant limitations on capacity expansion,often requiring physical replacement and causing service disruptions.Thermally tunable optical splitters address this challenge by enabling adjustable splitting ratios,but their operation is contingent upon a continuous power supply and complex driving systems.In this work,we present a novel,non-volatile tunable PLC platform based on Sb_(2)S_(3)phase-change materials.The proposed device,which incor-porates a Mach-Zehnder interferometer(MZI)optical switch structure,offers tunable splitting ratios via laser-direct writing or ohmic heating,providing flexible reconfiguration capabilities.Experimental results demonstrate non-volatile power splitting ranging from 50∶50 to 20∶80,with a modest increase of approximately 1 dB in additional loss.This work highlights the potential of the proposed platform for low-power,high-efficiency,and reconfigurable photonic networks.
基金supported by the Youth Teacher Capability Enhancement Plan Overseas Visiting Scholar Program.
文摘Graphene-lithium niobate(G-LN)integration has emerged as a promising approach for advancing acoustoelectric,photonic,and optic devices.This hybrid integration leverages graphene’s remarkable optical transparency,excellent conductivity,high carrier mobility,tunable electronic properties,and compatibility with complementary metal oxide semiconductor technology,alongside LN’s high electro-optic,acousto-optic,and nonlinearoptic coefficients,creating a highly functional platform for novel devices.This mini-review comprehensively synthesizes the state-of-the-art and recent advancements in G-LN integration,summarizing its fundamental principles and processes of practical fabrication techniques,and exploring surface acoustic waves,graphene electrodes,surface plasmon polaritons,and graphene absorbers.This mini-review of G-LN integration could underscore its significance in supporting more robust,energy-efficient,high-performance,and uniquely diverse devices,implying its potential to drive breakthroughs across multiple disciplines,as well as inspire further advancements in G-LN integration-based device design and applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.12104374,12164042,and 12264045)the Natural Science Foundation of Gansu Province,China(Grant No.20JR5RA526).
文摘We investigate nonreciprocal transmission in microcavity exciton polaritons and obtain analytical conditions for achieving unidirectional and circular transmission.The phase difference between two effective optomechanical couplings can regulate the interference of different channels between two photon modes,and control the direction of nonreciprocity,resulting in unidirectional forward and backward transmissions.Perfect nonreciprocal unidirectional transmission with zero losses is realized,which depends on exciton-photon-phonon couplings.Moreover,clockwise and counterclockwise circular transmissions are implemented by appropriately adjusting the phase of photon mode couplings.Our results open up exciting possibilities for implementing nonreciprocal photonic devices.
基金financial support from National Natural Science Foundation of China(No.61775120).
文摘Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.
基金Project supported by the Applied Physics Research Centre of Imam Hossein University, Tehran, Iran (180/207/531-1388/5/5)
文摘Nd3＋,Eu3＋ and Tb3＋ ions doped transparent chlorophosphate glass ceramics were prepared and their frequency-conversion properties were studied. X-ray diffraction （XRD） patterns evidenced the formation of expected halide nanocrystals. The absorption,excitation and emission spectra investigation indicated that some of rare earth （RE） ions were trapped in low phonon energy halide nanocrystals,and therefore an efficient down frequency-conversion was observed. The comparative spectroscopic studies of RE doped samples suggested that the glass ceramics systems are potentially applicable as efficient ultraviolet to visible frequency-conversion photonics materials.
基金the financial support from Shenzhen Science and Technology Program (JCYJ20210324142210027, X.D.)the National Natural Science Foundation of China (52103136, 22275028, U22A20153, 22102017, 22302033, and 52106194)+5 种基金the Sichuan Outstanding Young Scholars Foundation (2021JDJQ0013)Natural Science Foundation of Sichuan Province (2022NSFSC1271)Sichuan Science and Technology Program (2023JDRC0082)“Oncology Medical Engineering Innovation Foundation” project of University of Electronic Science and Technology of China and Sichuan Cancer Hospital (ZYGX2021YGCX009)“Medical and Industrial Cross Foundation” of University of Electronic Science and Technology of China and Sichuan Provincial People’s Hospital (ZYGX2021YGLH207)Shandong Key R&D grant (2022CXGC010509)。
文摘Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.
基金supported by the National Key R&D Program of China(2021YFA1401103)the National Natural Science Foundation of China(61925502 and 51772145).
文摘Systemic blood circulation is one of life activity’s most important physiological functions.Continuous noninvasive hemodynamicmonitoring is essential for the management of cardiovascular status.However,it is difficult to achieve systemichemodynamic monitoring with the daily use of current devices due to the lack of multichannel and time-synchronized operationcapability over the whole body.Here,we utilize a soft microfiber Bragg grating group to monitor spatiotemporalhemodynamics by taking advantage of the high sensitivity,electromagnetic immunity,and great temporal synchronizationbetween multiple remote sensor nodes.A continuous systemic hemodynamic measurement technique is developedusing all-mechanical physiological signals,such as ballistocardiogram signals and pulse waves,to illustrate the actualmechanical process of blood circulation.Multiple hemodynamic parameters,such as systemic pulse transit time,heartrate,blood pressure,and peripheral resistance,are monitored using skin-like microfiber Bragg grating patches conformallyattached at different body locations.Relying on the soft microfiber Bragg grating group,the spatiotemporal hemodynamicmonitoring technique opens up new possibilities in clinical medical diagnosis and daily health management.
基金the National Natural Science Foundation of China(Grant No.11935010)the Opening Project of Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology。
文摘The passive radiative cooling technology shows a great potential application on reducing the enormous global energy consumption.The multilayer metamaterials could enhance the radiative cooling performance.However,it is a challenge to design the radiative cooler.In this work,based on the particle swarm optimization(PSO)evolutionary algorithm,we develop an intelligent workflow in designing photonic radiative cooling metamaterials.Specifically,we design two 10-layer SiO_(2) radiative coolers doped by cylindrical MgF_(2) or air impurities,possessing high emissivity within the selective(8–13μm)and broadband(8–25μm)atmospheric transparency windows,respectively.Our two kinds of coolers demonstrate power density as high as 119 W/m^(2) and 132 W/m^(2) at the room temperature(300 K).Our scheme does not rely on the usage of special materials,forming high-performing metamaterials with conventional poor-performing components.This significant improvement of the emission spectra proves the effectiveness of our inverse design algorithm in boosting the discovery of high-performing functional metamaterials.
基金Project supported by the National Undergraduate Training Projects for Innovation and Entrepreneurship (Grant No. 5003182007)the National Natural Science Foundation of China (Grant No. 12074137)+1 种基金the National Key Research and Development Project of China (Grant No. 2021YFB2801903)the Natural Science Foundation from the Science,Technology,and Innovation Commission of Shenzhen Municipality (Grant No. JCYJ20220530161010023)。
文摘Optical mode converters are essential for enhancing the capacity of optical communication systems. However, fabrication errors restrict the further improvement of conventional mode converters. To address this challenge, we have designed an on-chip TE0–TE1mode converter based on topologically protected waveguide arrays. The simulation results demonstrate that the converter exhibits a mode coupling efficiency of 93.5% near 1550 nm and can tolerate a relative fabrication error of 30%. Our design approach can be extended to enhance the robustness for other integrated photonic devices, beneficial for future development of optical network systems.
文摘A modified wide-angle beam propagation based on the Douglas operators is presented.The truncation error in the modified wide-angle beam propagation is reduced to o (Δ x ) 4 in the transverse direction nearly without any increase of the computation time,whereas the error in the ordinary wide-angle beam propagation method is typically o (Δ x ) 2.With trivial programming changes,the accuracy is higher,especially in wide-angle propagation.
基金supported by the Research Grants Council(RGC)of Hong Kong(Grant Nos.15215620 and N_PolyU511/20)the Innovation and Technology Commission(ITC)of Hong Kong(Grant Nos.ITF-MHKJFS,MHP/085/22,and PiH/236/24)+2 种基金The Hong Kong Polytechnic University(Grant Nos.1-CD4V,1-CD6U,G-SB6C,1-CD8U,1-BBEN,1-W28S,1-CD9Q,1-SBVB,1-CDJW,1-CDJ8,and 1-W32A)the BROMEDIR European project(Grant No.101092697)the National Natural Science Foundation of China(Grant No.62405257).
文摘The rapid advancement of renewable energy technologies is essential for combating global climate change and achieving energy sustainability.Among the various renewable sources,solar energy stands out,with silicon playing a pivotal role in solar energy conversion.However,traditional silicon-based devices often face challenges due to high surface reflectance,which limits their efficiency.The emergence of black silicon(b-Si)offers a transformative solution,thanks to its micro-and nanoscale structures that provide ultra-low reflectivity and enhanced light absorption.This makes b-Si an ideal candidate for improving solar energy devices.Beyond solar energy applications,b-Si has drawn notable interest in photonics,including applications in photodetectors,surface-enhanced Raman scattering,and imaging.This review explores b-Si comprehensively,discussing its fabrication processes,distinctive properties,and contributions to both solar energy conversion and photonic technologies.Key topics include its roles in solar cells,photoelectrochemical systems,solar thermal energy conversion,and advanced photonic devices.Furthermore,the review addresses the challenges and future directions for optimizing b-Si to facilitate its practical deployment across a range of energy and photonic applications.
基金National Key Research and Development Program of China(2024YFB2908302)National Science Fund for Distinguished Young Scholars(61725503)+5 种基金National Natural Science Foundation of China(U23B2047,62321166651,92150302,62375240)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2021R01001)Zhejiang Provincial Major Research and Development Program(2021C01199)Natural Science Foundation of Zhejiang Province(LZ22F050006)Fundamental Research Funds for the Central UniversitiesStartup Foundation for Hundred-Talent Program of Zhejiang University。
文摘Reconfigurable silicon microrings have garnered significant interest for addressing challenges in artificial intelligence,the Internet of Things,and telecommunications due to their versatile capabilities.Compared to electrooptic(EO)and thermo-optic(TO)devices,emerging micro-electromechanical systems(MEMS)-based reconfigurable silicon photonic devices actuated by electrostatic forces offer near-zero static power consumption.This study proposes and implements novel designs for fully reconfigurable silicon photonic MEMS microrings for high-speed dense wavelength division multiplexing(DWDM)elastic networks.The designs include an all-pass microring with a 7 nm free spectral range(FSR)and full-FSR resonance tuning range,an add-drop microring with a 3.5 nm FSR and full-FSR tuning range,and an add-drop double-microring with a 34 nm FSR,wide-range discrete resonance tunability,and flat-top tunability.These advancements hold promise for practical applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204274,12174222,12304364,and 12361141815)Key Research and Development Program of Shandong Province(Grant No.2024ZLGX02-3)+1 种基金Natural Science Foundation of Shandong Province(Grant Nos.ZR2022QA033,ZR2021ZD02,and ZR2023QA125)Taishan Scholar Foundation of Shandong Province(Grant No.tspd20210303).
文摘The femtosecond laser direct writing technique is a highly precise processing method that enables the rapid fabrication of three-dimensional(3D)micro-and nanoscale photonic structures in transparent materials.By focusing ultrashort laser pulses into transparent optical materials,such as crystals and glasses,it is possible to efficiently modify specific optical properties,including refractive indices and ferroelectric domains,at the laser focus.By carefully designing and optimizing the movement trajectory of the femtosecond laser,one can achieve periodic modulation of the optical features of these materials in 3D space.The resulting changes in material properties are closely linked to both the processing parameters of the femtosecond laser and the types of materials used.Through ongoing optimization of these parameters,desired periodic photonic structures can be created in specific transparent optical materials,leading to the development of 3D nonlinear photonic crystals(NPCs)and 3D waveguide arrays.Femtosecond laser direct writing breaks through the limitations of traditional techniques to fabricate 3D NPCs[e.g.,3D lithium niobate(LiNbO_(3))NPCs]and complex waveguide arrays(e.g.,3D helical waveguide arrays),realizing a paradigm shift in the fabrication of complex periodic photonic structures.To date,femtosecond-laser-written 3D NPCs and waveguide arrays have found extensive applications in integrated photonics,nonlinear optics,quantum optics,and topological photonics.We highlight recent advancements in femtosecond-laser-written 3D NPCs and waveguide arrays,such as pivotal breakthroughs in the fabrication of nanoscale-resolution 3D NPCs in LiNbO_(3).Finally,several potential research directions,such as the formation mechanism of domain wall and inducing millimeter-scale domain inversion with femtosecond Bessel beam,have been proposed at the end of this article.
基金support from the University Grants Committee/Research Grants Council of the Hong Kong Special Administrative Region,China[Project No.AoE/P-502/20,CRF Project:C5031-22G,C5078-24G,GRF Project:CityU11305223,CityU11300224,CityU11304925,CityU11305125]City University of Hong Kong[Project No.9380131]National Natural Science Foundation of China[Grant No.62375232].
文摘Meta-devices,known for their capability to manipulate light fields at a subwavelength scale,have gained significant traction in the realm of quantum photonics in recent years.They are being utilized in miniaturized applications such as the preparation of quantum light sources and the control and detection of quantum states.In this review,we provide a systematic explanation of the working principles and notable applications of metadevices in quantum optical information processing,while also outlining potential directions for the future development of quantum meta-devices.
