The quaternion approach to solve the coupled nonlinear Schrodinger equations （CNSEs） in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled qua...The quaternion approach to solve the coupled nonlinear Schrodinger equations （CNSEs） in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled quater- nion. The crosstalk of quarter-phase-shift-key signals caused by fiber nonlinearity in polarization multiplexing systems with 100 Cbps bit-rate is investigated and simulated. The results demonstrate that the crosstalk is like a rotated ghosting of input constellation. For the 50 km conventional fiber link, when the total power is less than 4roW, the crosstalk effect can be neglected; when the power is larger than 20roW, the crosstalk is very obvious. In addition, the crosstalk can not be detected according to the output eye diagram and state of polarization in Poincare sphere in the trunk fiber, making it difficult for the monitoring of optical trunk link.展开更多
We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying （PDM-QPSK） signal transmission over fiber, wireless and fiber at Wband （75-110 GH...We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying （PDM-QPSK） signal transmission over fiber, wireless and fiber at Wband （75-110 GHz）. The generation of polarization multiplexing millimeter-wave （mm-wave） wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2~2 multiple-input multiple-output （MIMO） wireless link. At the receiver base station （BS）, polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm （CMA） is applied for polarization de-multiplexing. The bit-error-ratio （BER） for 16-Gb/s PDM- QPSK signal delivery is below the forward-error-correction （FEC） threshold of 3.8× 10-3 with the optical signal-to-noise ratio （OSNR） above 11.8 dB.展开更多
Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and e...Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied,the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.展开更多
A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system con...A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirm low optical loss and environmental stabilities.展开更多
Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division mul...Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.展开更多
Traditional tunable metasurfaces have evolved through mechanisms relying on external stimuli,such as electrical,thermal,or optical excitation,to dynamically control electromagnetic(EM)wavefronts.While these approaches...Traditional tunable metasurfaces have evolved through mechanisms relying on external stimuli,such as electrical,thermal,or optical excitation,to dynamically control electromagnetic(EM)wavefronts.While these approaches enable functionalities like focal varying and polarization modulation,they suffer from inherent limitations,including energy inefficiency,structural complexity,and limited adaptability.Here,cascaded all-dielectric Moirémetasurfaces are introduced,which are capable of simultaneous polarization multiplexing and focal-length control for terahertz(THz)beams without external stimuli.Moirédevice 1 combines polarization-insensitive(Layer 1)and polarization-sensitive(Layer 2)meta-atoms to independently tailor orthogonal circular polarization channels,including left-handed circular polarization(LCP)and right-handed circular polarization(RCP).Under circularly polarized illumination,it generates focused beams with distinct topological charges(l=0 for LCP→RCP and l=1 for RCP→LCP),while relative layer rotation enables continuous focal-length adjustment from 9.28 mm to3.22 mm,accompanied by a numerical aperture(NA)increase from 0.54 to 0.88.Moirédevice 2 extends this paradigm to orthogonal linear polarization(LP)channels,producing l=1 and l=0 beams under x-LP and y-LP illumination,with a zoom range of 8.42–3.11 mm and NA up to 0.88.Experimental results validate polarization-selective focusing with efficiency exceeding 15%and robust agreement with simulation results,and the calculated absolute percentage errors(APEs)are below 5.9%for focal length and 3%for NA.These values are consistent with the expected theoretical trends,demonstrating that the experimental results align well with the predicted performance.This reconfigurable system introduces additional control dimensions through mechanical adjustments to cascaded metasurfaces,paving the way for adaptive wavefront control and opening new avenues for next-generation optical technologies.展开更多
In microwave communication systems,focusing and imaging have attracted widespread attention due to their application prospects in the information processing and communication fields.Most existing multi-channel focusin...In microwave communication systems,focusing and imaging have attracted widespread attention due to their application prospects in the information processing and communication fields.Most existing multi-channel focusing and imaging are implemented by interleaved metasurfaces.However,the disadvantages of their large size and low efficiency limit their practical applications in large-capacity and low-loss integrated systems.To solve these issues,here,we propose a non-interleaved polarization-frequency multiplexing metasurface for high-efficiency multi-channel focusing and imaging.The meta-atoms of the non-interleaved metasurface are composed of a metallic ground plate,two dielectric layers,a larger cross-shaped metal structure,and a smaller cross-shaped metal structure embedded by a circular metal aperture.By altering the size of two cross-shaped structures,the designed meta-atom can obtain the independent complete 2π phase coverage with high reflection efficiency at two different frequency ranges for two orthogonal linear polarization(LP)incidences,realizing polarization multiplexing and frequency multiplexing.Moreover,two types of metasurfaces based on the above meta-atoms are designed to realize multi-channel focusing and imaging with high efficiency.As a proof,the focusing metasurface is fabricated and measured,and the measured results are well consistent with simulated results.Therefore,the proposed scheme has the advantages of high efficiency,multi-channel,and compact size,which possesses broad application prospects in low-loss and multichannel communication integrated systems.展开更多
This study introduced a differential polarization division multiplexing(DPDM)scheme for all-fiber high-accuracy spectral measurement.Launching two orthogonal linearly polarized light beams into multimode fibers,the DP...This study introduced a differential polarization division multiplexing(DPDM)scheme for all-fiber high-accuracy spectral measurement.Launching two orthogonal linearly polarized light beams into multimode fibers,the DPDM elegantly reconstructs the input spectra from the differential speckle,which is more comprehensive spectral-to-spatial encoding with fewer noises and better contrast.A spectral measurement with 2 pm resolution and 2000 channels was achieved.Compared with traditional transmission matrix and polarization division multiplexing schemes,the proposed DPDM approach reduced the spectral reconstruction error by 77%and 69%,respectively,offering a simple and effective solution for highly accurate spectral measurements.展开更多
100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission...100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission systems have been discussed.It is demonstrated that optical OFDM can be used in future 100 Gb/s/ch and long-haul system.展开更多
Polarizing beam splitter has rather significant applications in polarization diversity circuits and polarization multiplexing systems.In this paper,we present an asymmetric polarizing beam splitter utilizing hybrid pl...Polarizing beam splitter has rather significant applications in polarization diversity circuits and polarization multiplexing systems.In this paper,we present an asymmetric polarizing beam splitter utilizing hybrid plasmonic waveguide.The special hybrid structure with a hybrid waveguide and a dielectric waveguide can limit the energy of TE and TM modes to a different layer.Therefore,we can achieve beam splitting by adjusting the corresponding parameters of the two waveguides.First,we studied the influences of different structure parameters on the real part of the effective mode refractive index of the two waveguides,and obtained a set of parameters that satisfy the condition of strong coupling of TM mode and weak coupling of TE mode.Then,the performance of our proposed polarizing beam splitter is evaluated numerically.The length of the coupling section is only 4.1μm,and the propagation loss of TM and TE modes is 0.0025 d B/μm and 0.0031 d B/μm respectively.Additionally,the extinction ratios of TM and TE modes are 10.62 d B and 12.55 d B,respectively.Particularly,the proposed device has excellent wavelength insensitivity.Over the entire C-band,the fluctuation of the whole normalized output power is less than 0.03.In short,our proposed asymmetric polarizing beam splitter features ultra-compactness,low propagation loss,and broad bandwidth,which would provide promising applications in polarization multiplexing system and polarization diversity circuits relevant to optical interconnection.展开更多
We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to dem...We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to demultiplex the signal multiplexed and improve it with a conjugated gradient algorithm. We experimentally resume the polarization state with a deviation under 5% and the power loss less than 20 dB which proves the feasibility of the polarization control algorithm in the new polarization multiplexing system.展开更多
Polarization division multiplexing (PDM) can double the spectral efficiency of an optical transmission system. By means of simulation, the 2x40Gbit/s NRZ PDM system performance under polarization mode dispersion (PMD)...Polarization division multiplexing (PDM) can double the spectral efficiency of an optical transmission system. By means of simulation, the 2x40Gbit/s NRZ PDM system performance under polarization mode dispersion (PMD) and chromatic dispersion has been investigated. To realize the best performance, the bit slots of the two channels should be synchronized.展开更多
Electromagnetic waves carrying orbital angular momentum(OAM),namely OAM beams,are important in various fields including optics,communications,and quantum information.However,most current schemes can only generate sing...Electromagnetic waves carrying orbital angular momentum(OAM),namely OAM beams,are important in various fields including optics,communications,and quantum information.However,most current schemes can only generate single or several simple OAM modes.Multi-mode OAM beams are rarely seen.This paper proposes a scheme to design metasurfaces that can generate multiple polarization-multiplexed OAM modes with equal intervals and intensities(i.e.,OAM combs)working in the terahertz(THz)range.As a proof of concept,we first design a metasurface to generate a pair of polarization-multiplexed OAM combs with arbitrary mode numbers.Furthermore,another metasurface is proposed to realize a pair of polarization-multiplexed OAM combs with arbitrary locations and intervals in the OAM spectrum.Experimental results agree well with full-wave simulations,verifying a great performance of OAM combs generation.Our method may provide a new solution to designing high-capacity THz devices used in multi-mode communication systems.展开更多
Silicon is a common material of choice for semiconductor optics in the infrared spectral range,due to its low cost,well-developed high-volume manufacturing methods,high refractive index,and transparency.It is,however,...Silicon is a common material of choice for semiconductor optics in the infrared spectral range,due to its low cost,well-developed high-volume manufacturing methods,high refractive index,and transparency.It is,however,typically ill-suited for applications in the visible range,due to its large absorption coefficient,especially for green and blue light.Counterintuitively,we demonstrate how ultra-thin crystalline meta-optics enable full-color imaging in the visible range.For this purpose,we employ an inverse design approach,which maximizes the volume under the broadband modulation transfer function of the meta-optics.Beyond that,we demonstrate polarization-multiplexed functionality in the visible.This is particularly important as polarization optics require high index materials,a characteristic often difficult to obtain in the visible.展开更多
Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most m...Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most metalenses still only work as a substitution of conventional lenses in optical settings,whose integration advantage is rarely manifested.We propose a highly integrated imaging device with silicon metalenses directly mounted on a complementary metal oxide semiconductor image sensor,whose working distance is in hundreds of micrometers.The imaging performances including resolution,signal-to-noise ratio,and field of view(FOV)are investigated.Moreover,we develop a metalens array with polarization-multiplexed dual-phase design for a wide-field microscopic imaging.This approach remarkably expands the FOV without reducing the resolution,which promises a non-limited space-bandwidth product imaging for wide-field microscopy.As a result,we demonstrate a centimeter-scale prototype for microscopic imaging,showing uniqueness of meta-design for compact integration.展开更多
InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultr...InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultra-high speed electro-absorption modulated lasers(EML)which represent a simple transmitter PIC comprising a singlemode laser diode and an electro-absorption modulator.Using a so-called identicallayer approach single-wavelength modulation rates up to 100 Gb/s have been accomplished.By additionally integrating an optical amplifier section modulated optical output power of>10 dBm has been achieved.Multi-level amplitude modulation was successfully demonstrated.Extended EML chips designed for wavelength-division and space-division multiplexing,respectively,will be presented.For dual-polarization transmission a novel EML related transmitter as well as a corresponding receiver PIC have been introduced.The latter devices were made on a generic PIC platform that is available for open-access foundry service.展开更多
We present the performance analysis of ll2Gb/s-4 wavelength division multiplexing （WDM） 100GHz channel spacing polarization division multiplexed-differential quadrature phase shift keying （PDM-DQPSK） optical label...We present the performance analysis of ll2Gb/s-4 wavelength division multiplexing （WDM） 100GHz channel spacing polarization division multiplexed-differential quadrature phase shift keying （PDM-DQPSK） optical label switching system with frequency swept coherent detected spectral amplitude code labels. Direct detection is chosen to demodulate the payload by applying a polarization tracker, while 4-bits of 156Mb/s spectral amplitude code label is coherently detected with a scheme of frequently-swept coherent detection. We optimize the payload laser linewidth as well as the frequency spacing between the payload and label. The label and payload signal performances are assessed by the eye-diagram opening factor （EOF） and bit-error rate （BER） at 10 9 as a function of the received optical power （ROP） and the optical signal to noise ratio （OSNR）. The payload could well be demodulated after 900 km at a bit error rate of 10-3 using forward error correction （FEC）.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61275075the Beijing Natural Science Foundation under Grant Nos 4132035 and 4144080
文摘The quaternion approach to solve the coupled nonlinear Schrodinger equations （CNSEs） in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled quater- nion. The crosstalk of quarter-phase-shift-key signals caused by fiber nonlinearity in polarization multiplexing systems with 100 Cbps bit-rate is investigated and simulated. The results demonstrate that the crosstalk is like a rotated ghosting of input constellation. For the 50 km conventional fiber link, when the total power is less than 4roW, the crosstalk effect can be neglected; when the power is larger than 20roW, the crosstalk is very obvious. In addition, the crosstalk can not be detected according to the output eye diagram and state of polarization in Poincare sphere in the trunk fiber, making it difficult for the monitoring of optical trunk link.
基金supported by the National Natural Science Foundation of China(Nos.61177071and 61250018)the National"863"Program of China(Nos.2011AA010302 and 2012AA011302)+1 种基金the National Key Technology R&D Program of China(No.2012BAH18B00)the International Cooperation Program of Shanghai Science and Technology Association(No.12510705600)
文摘We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying （PDM-QPSK） signal transmission over fiber, wireless and fiber at Wband （75-110 GHz）. The generation of polarization multiplexing millimeter-wave （mm-wave） wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2~2 multiple-input multiple-output （MIMO） wireless link. At the receiver base station （BS）, polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm （CMA） is applied for polarization de-multiplexing. The bit-error-ratio （BER） for 16-Gb/s PDM- QPSK signal delivery is below the forward-error-correction （FEC） threshold of 3.8× 10-3 with the optical signal-to-noise ratio （OSNR） above 11.8 dB.
基金supported by the National Key R&D Program of China (Nos. 2021YFB2801803 and 2021YFA1401200)the Natural Science Foundation of Shandong Province(No. ZR2023LZH001)+3 种基金the Beijing Outstanding Young Scientist Program (No. BJJWZYJH01201910007022)the National Natural Science Foundation of China (Nos. U21A20140 and 92050117)the Fok Ying-Tong Education Foundation of China(No. 161009)the Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park (No. Z211100004821009)。
文摘Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied,the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.
基金This research is supported by a grant from FUTABA DENSHI foundation.
文摘A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirm low optical loss and environmental stabilities.
基金financially supported by the Russian Foundation for Basic Research(grant No.18-29-20045)for WDM,MDM and hybrid WDM-MDM,WDM-PDM sectionsthe Russian Science Foundation(grant No.21-79-20075)for PDM,OAMM and hybrid PDM-MDM sectionsthe Ministry of Science and Higher Education of the Russian Federation under the FSRC"Crystallography and Photonics"of the Russian Academy of Sciences(the state task No.007-GZ/Ch3363/26)for comparative analysis.
文摘Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.
基金National Natural Science Foundation of China(U22A2008,12404484,62405219)Sichuan Provincial Science and Technology Support Program(25QNJJ2419)+1 种基金National Key Research and Development Program of China(2021YFB2800703)Laoshan Laboratory Science and Technology Innovation Project(LSKJ202200801)。
文摘Traditional tunable metasurfaces have evolved through mechanisms relying on external stimuli,such as electrical,thermal,or optical excitation,to dynamically control electromagnetic(EM)wavefronts.While these approaches enable functionalities like focal varying and polarization modulation,they suffer from inherent limitations,including energy inefficiency,structural complexity,and limited adaptability.Here,cascaded all-dielectric Moirémetasurfaces are introduced,which are capable of simultaneous polarization multiplexing and focal-length control for terahertz(THz)beams without external stimuli.Moirédevice 1 combines polarization-insensitive(Layer 1)and polarization-sensitive(Layer 2)meta-atoms to independently tailor orthogonal circular polarization channels,including left-handed circular polarization(LCP)and right-handed circular polarization(RCP).Under circularly polarized illumination,it generates focused beams with distinct topological charges(l=0 for LCP→RCP and l=1 for RCP→LCP),while relative layer rotation enables continuous focal-length adjustment from 9.28 mm to3.22 mm,accompanied by a numerical aperture(NA)increase from 0.54 to 0.88.Moirédevice 2 extends this paradigm to orthogonal linear polarization(LP)channels,producing l=1 and l=0 beams under x-LP and y-LP illumination,with a zoom range of 8.42–3.11 mm and NA up to 0.88.Experimental results validate polarization-selective focusing with efficiency exceeding 15%and robust agreement with simulation results,and the calculated absolute percentage errors(APEs)are below 5.9%for focal length and 3%for NA.These values are consistent with the expected theoretical trends,demonstrating that the experimental results align well with the predicted performance.This reconfigurable system introduces additional control dimensions through mechanical adjustments to cascaded metasurfaces,paving the way for adaptive wavefront control and opening new avenues for next-generation optical technologies.
基金National Natural Science Foundation of China(62075052,6227419)National Key Research and Development Program of China(2024YFE0108300)+2 种基金Science and Technology Major Project of Guangxi,China(Gui Ke AA21077015,Gui Ke AA24263032)Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(JCKYS2020603C009,6142905212711)Project of Innovative and Entrepreneurship Training Program for College Students in Heilongjiang Province(201810214105)。
文摘In microwave communication systems,focusing and imaging have attracted widespread attention due to their application prospects in the information processing and communication fields.Most existing multi-channel focusing and imaging are implemented by interleaved metasurfaces.However,the disadvantages of their large size and low efficiency limit their practical applications in large-capacity and low-loss integrated systems.To solve these issues,here,we propose a non-interleaved polarization-frequency multiplexing metasurface for high-efficiency multi-channel focusing and imaging.The meta-atoms of the non-interleaved metasurface are composed of a metallic ground plate,two dielectric layers,a larger cross-shaped metal structure,and a smaller cross-shaped metal structure embedded by a circular metal aperture.By altering the size of two cross-shaped structures,the designed meta-atom can obtain the independent complete 2π phase coverage with high reflection efficiency at two different frequency ranges for two orthogonal linear polarization(LP)incidences,realizing polarization multiplexing and frequency multiplexing.Moreover,two types of metasurfaces based on the above meta-atoms are designed to realize multi-channel focusing and imaging with high efficiency.As a proof,the focusing metasurface is fabricated and measured,and the measured results are well consistent with simulated results.Therefore,the proposed scheme has the advantages of high efficiency,multi-channel,and compact size,which possesses broad application prospects in low-loss and multichannel communication integrated systems.
基金supported by the National Natural Science Foundation of China(No.62305391)the Hunan Innovative Province Construction Project(No.2019RS3017)+1 种基金the National Postdoctoral Program for Innovative Talents(No.BX20190063)the Scientific Fund of National University of Defense Technology(Nos.22-061 and 24ZZCX-BC-03)。
文摘This study introduced a differential polarization division multiplexing(DPDM)scheme for all-fiber high-accuracy spectral measurement.Launching two orthogonal linearly polarized light beams into multimode fibers,the DPDM elegantly reconstructs the input spectra from the differential speckle,which is more comprehensive spectral-to-spatial encoding with fewer noises and better contrast.A spectral measurement with 2 pm resolution and 2000 channels was achieved.Compared with traditional transmission matrix and polarization division multiplexing schemes,the proposed DPDM approach reduced the spectral reconstruction error by 77%and 69%,respectively,offering a simple and effective solution for highly accurate spectral measurements.
基金supported by NSFC(no60872035)Youthful foundation of UESTC JX0707Key Youthful foundation of UESTC JX0801
文摘100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission systems have been discussed.It is demonstrated that optical OFDM can be used in future 100 Gb/s/ch and long-haul system.
基金supported by the Shenzhen Science and Technology Program(JCYJ20210324093806017)the ShenzhenHong Kong Joint Innovation Foundation(SGDX20190919094401725)。
文摘Polarizing beam splitter has rather significant applications in polarization diversity circuits and polarization multiplexing systems.In this paper,we present an asymmetric polarizing beam splitter utilizing hybrid plasmonic waveguide.The special hybrid structure with a hybrid waveguide and a dielectric waveguide can limit the energy of TE and TM modes to a different layer.Therefore,we can achieve beam splitting by adjusting the corresponding parameters of the two waveguides.First,we studied the influences of different structure parameters on the real part of the effective mode refractive index of the two waveguides,and obtained a set of parameters that satisfy the condition of strong coupling of TM mode and weak coupling of TE mode.Then,the performance of our proposed polarizing beam splitter is evaluated numerically.The length of the coupling section is only 4.1μm,and the propagation loss of TM and TE modes is 0.0025 d B/μm and 0.0031 d B/μm respectively.Additionally,the extinction ratios of TM and TE modes are 10.62 d B and 12.55 d B,respectively.Particularly,the proposed device has excellent wavelength insensitivity.Over the entire C-band,the fluctuation of the whole normalized output power is less than 0.03.In short,our proposed asymmetric polarizing beam splitter features ultra-compactness,low propagation loss,and broad bandwidth,which would provide promising applications in polarization multiplexing system and polarization diversity circuits relevant to optical interconnection.
基金supported by the Key Item of Application Basis Research Plan of Tianjin under Grant No.06YFJZJC00400.
文摘We describe a new algorithm in a cost effective polarization division multiplexing （PDM） system. Without modifying the existing transmitter, receiver electronics, or softwares, we use a special optical scheme to demultiplex the signal multiplexed and improve it with a conjugated gradient algorithm. We experimentally resume the polarization state with a deviation under 5% and the power loss less than 20 dB which proves the feasibility of the polarization control algorithm in the new polarization multiplexing system.
文摘Polarization division multiplexing (PDM) can double the spectral efficiency of an optical transmission system. By means of simulation, the 2x40Gbit/s NRZ PDM system performance under polarization mode dispersion (PMD) and chromatic dispersion has been investigated. To realize the best performance, the bit slots of the two channels should be synchronized.
基金support from the National Key Research and Development Program of China(No.2019YFA0210203)the National Natural Science Foundation of China(No.62271011,No.61971013).
文摘Electromagnetic waves carrying orbital angular momentum(OAM),namely OAM beams,are important in various fields including optics,communications,and quantum information.However,most current schemes can only generate single or several simple OAM modes.Multi-mode OAM beams are rarely seen.This paper proposes a scheme to design metasurfaces that can generate multiple polarization-multiplexed OAM modes with equal intervals and intensities(i.e.,OAM combs)working in the terahertz(THz)range.As a proof of concept,we first design a metasurface to generate a pair of polarization-multiplexed OAM combs with arbitrary mode numbers.Furthermore,another metasurface is proposed to realize a pair of polarization-multiplexed OAM combs with arbitrary locations and intervals in the OAM spectrum.Experimental results agree well with full-wave simulations,verifying a great performance of OAM combs generation.Our method may provide a new solution to designing high-capacity THz devices used in multi-mode communication systems.
基金supported by DARPA W31P4Q21C0043.Part of this work was conducted at the Washington Nanofabrication Facility/Molecular Analysis Facility,a National Nanotechnology Coordinated Infrastructure(NNCI)site at the University of Washington,with partial support from the National Science Foundation via awards NNCI-1542101,and NNCI-2025489.
文摘Silicon is a common material of choice for semiconductor optics in the infrared spectral range,due to its low cost,well-developed high-volume manufacturing methods,high refractive index,and transparency.It is,however,typically ill-suited for applications in the visible range,due to its large absorption coefficient,especially for green and blue light.Counterintuitively,we demonstrate how ultra-thin crystalline meta-optics enable full-color imaging in the visible range.For this purpose,we employ an inverse design approach,which maximizes the volume under the broadband modulation transfer function of the meta-optics.Beyond that,we demonstrate polarization-multiplexed functionality in the visible.This is particularly important as polarization optics require high index materials,a characteristic often difficult to obtain in the visible.
基金The authors acknowledge the financial support from the National Key R&D Program of China(Nos.2016YFA0202103 and 2017YFA0303701)the National Natural Science Foundation of China(Nos.91850204 and 11674167)Tao Li thanks the Dengfeng Project B of Nanjing University for the support.The authors declare that they have no conflicts of interest.
文摘Metasurfaces have demonstrated unprecedented capabilities in manipulating light with ultrathin and flat architectures.Although great progress has been made in the metasurface designs and function demonstrations,most metalenses still only work as a substitution of conventional lenses in optical settings,whose integration advantage is rarely manifested.We propose a highly integrated imaging device with silicon metalenses directly mounted on a complementary metal oxide semiconductor image sensor,whose working distance is in hundreds of micrometers.The imaging performances including resolution,signal-to-noise ratio,and field of view(FOV)are investigated.Moreover,we develop a metalens array with polarization-multiplexed dual-phase design for a wide-field microscopic imaging.This approach remarkably expands the FOV without reducing the resolution,which promises a non-limited space-bandwidth product imaging for wide-field microscopy.As a result,we demonstrate a centimeter-scale prototype for microscopic imaging,showing uniqueness of meta-design for compact integration.
基金For the development of the generic PIC platform outlined in the article funding has been received from the European Commission through the projects EuroPIC(www.europic.jeppix.eu)PARADIGM(www.paradigm.jeppix.eu),and InPulse(www.inpulse.jeppix.eu).The 4-array EML chips(refer to Fig.7)was developed in the framework of the PIANO+-ALOHA project(grant#01BP1125).The other topics have been conducted on HHI internal funding.
文摘InP technology is the principal enabler for implementing fully monolithic photonic integrated circuits(PIC),uniquely including transmitter elements.In this article we present an overview of recent achievements on ultra-high speed electro-absorption modulated lasers(EML)which represent a simple transmitter PIC comprising a singlemode laser diode and an electro-absorption modulator.Using a so-called identicallayer approach single-wavelength modulation rates up to 100 Gb/s have been accomplished.By additionally integrating an optical amplifier section modulated optical output power of>10 dBm has been achieved.Multi-level amplitude modulation was successfully demonstrated.Extended EML chips designed for wavelength-division and space-division multiplexing,respectively,will be presented.For dual-polarization transmission a novel EML related transmitter as well as a corresponding receiver PIC have been introduced.The latter devices were made on a generic PIC platform that is available for open-access foundry service.
文摘We present the performance analysis of ll2Gb/s-4 wavelength division multiplexing （WDM） 100GHz channel spacing polarization division multiplexed-differential quadrature phase shift keying （PDM-DQPSK） optical label switching system with frequency swept coherent detected spectral amplitude code labels. Direct detection is chosen to demodulate the payload by applying a polarization tracker, while 4-bits of 156Mb/s spectral amplitude code label is coherently detected with a scheme of frequently-swept coherent detection. We optimize the payload laser linewidth as well as the frequency spacing between the payload and label. The label and payload signal performances are assessed by the eye-diagram opening factor （EOF） and bit-error rate （BER） at 10 9 as a function of the received optical power （ROP） and the optical signal to noise ratio （OSNR）. The payload could well be demodulated after 900 km at a bit error rate of 10-3 using forward error correction （FEC）.
