Compressive sensing（CS） has emerged as a novel sampling framework which enables sparse signal acquisition and reconstruction with fewer measurements below the Nyquist rate.An important issue for CS is the constructi...Compressive sensing（CS） has emerged as a novel sampling framework which enables sparse signal acquisition and reconstruction with fewer measurements below the Nyquist rate.An important issue for CS is the construction of measurement matrix or sensing matrix.A new deterministic sensing matrix,named as OOC-B,is proposed by exploiting optical orthogonal codes（OOCs）,Bernoulli matrix and Singer structure,which has the entries of 0,＋1 and-1 before normalization.We have proven that the designed deterministic matrix is asymptotically optimal.In addition,the proposed deterministic sensing matrix is applied to direction of arrival（DOA） estimation of narrowband signals by CS arrays（CSA）processing and CS recovery.Theoretical analysis and simulation results show that the proposed sensing matrix has good performance for DOA estimation.It is very effective for simplifying hardware structure and decreasing computational complexity in DOA estimation by CSA processing.Besides,lower root mean square error（RMSE） and bias are obtained in DOA estimation by CS recovery.展开更多
The first path-independent insertion-loss（PILOSS） strictly non-blocking 4×4 silicon electro–optic switch matrix is reported. The footprint of this switch matrix is only 4.6 mm×1.0 mm. Using single-arm mod...The first path-independent insertion-loss（PILOSS） strictly non-blocking 4×4 silicon electro–optic switch matrix is reported. The footprint of this switch matrix is only 4.6 mm×1.0 mm. Using single-arm modulation, the crosstalk measured in this test is-13 dB --27 dB. And a maximum crosstalk deterioration of 6d B caused by two-path interference is also found.展开更多
Based on a strong inter-diagonal matrix and Taylor series expansions,an oversample reconstruction method was proposed to calibrate the optical micro-scanning error. The technique can obtain regular 2 ×2 microscan...Based on a strong inter-diagonal matrix and Taylor series expansions,an oversample reconstruction method was proposed to calibrate the optical micro-scanning error. The technique can obtain regular 2 ×2 microscanning undersampling images from the real irregular undersampling images,and can then obtain a high spatial oversample resolution image. Simulations and experiments show that the proposed technique can reduce optical micro-scanning error and improve the system＇s spatial resolution. The algorithm is simple,fast and has low computational complexity. It can also be applied to other electro-optical imaging systems to improve their spatial resolution and has a widespread application prospect.展开更多
Phase modulation is a crucial step when the frequency-based wavefront optimization technique is exploited to measure the optical transmission matrix(TM) of a scattering medium. We report a simple but powerful method, ...Phase modulation is a crucial step when the frequency-based wavefront optimization technique is exploited to measure the optical transmission matrix(TM) of a scattering medium. We report a simple but powerful method, direct digital frequency synthesis(DDS) technology to modulate the phase front of the laser and measure the TM. By judiciously modulating the phase front of a He–Ne laser beam, we experimentally generate a high quality focus at any targeted location through a 2 mm thick 120 grit ground glass diffuser, which is commercially used in laser display and laser holographic display for improving brightness uniformity and reducing speckle. The signal to noise ratio(SNR) of the clear round focus is 50 and the size is about 44 μm. Our study will open up new avenues for enhancing light energy delivery to the optical engine in laser TV to lower the power consumption, phase compensation to reduce the speckle noise, and controlling the lasing threshold in random lasers.展开更多
In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space divis...In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.展开更多
Currently,multicast survivability in optical network obtains more attention.This paper focuses on the field of multicast grooming shared protection in green optical network and designs a novel auxiliary graph and a sh...Currently,multicast survivability in optical network obtains more attention.This paper focuses on the field of multicast grooming shared protection in green optical network and designs a novel auxiliary graph and a shared matrix to address the survivable multicast resource consumption.This paper also proposes a new heuristic called Green Multicast Grooming algorithm based on spanning path Cross-Shared protection(GMGCSP),in which network reliability,energy efficiency and resource utilization are jointly considered.Simulation results testify that,compared to other algorithms,the proposed GMG-CSP not only has lower blocking probability and higher bandwidth utilization ratio,but also saves more energy.展开更多
Multiplexing technology serves as an effective approach to increase both information storage and transmission capability.However,when exploring multiplexing methods across various dimensions,the polarization dimension...Multiplexing technology serves as an effective approach to increase both information storage and transmission capability.However,when exploring multiplexing methods across various dimensions,the polarization dimension encounters limitations stemming from the finite orthogonal combinations.Given that only two mutually orthogonal polarizations are identifiable on the basic Poincarésphere,this poses a hindrance to polarization modulation.To overcome this challenge,we propose a construction method for the optical polarized orthogonal matrix(OPOM),which is not constrained by the number of orthogonal combinations.Furthermore,we experimentally validate its application in high-dimensional multiplexing of polarization holography.We explore polarization holography technology,capable of recording amplitude,phase,and polarization,for the purpose of recording and selective reconstruction of polarization multi-channels.Our research reveals that,despite identical polarization states,multiple images can be independently manipulated within distinct polarization channels through orthogonal polarization combinations,owing to the orthogonal selectivity among information.展开更多
This study introduces an optical neural network(ONN)-based autoencoder for efficient image processing,utilizing specialized optical matrix-vector multipliers for both encoding and decoding tasks.To address the challen...This study introduces an optical neural network(ONN)-based autoencoder for efficient image processing,utilizing specialized optical matrix-vector multipliers for both encoding and decoding tasks.To address the challenges in efficient decoding,we propose a method that optimizes output processing through scalar multiplications,enhancing performance in generating higher-dimensional outputs.By employing on-system iterative tuning,we mitigate hardware imperfections and noise,progressively improving image reconstruction accuracy to near-digital quality.Furthermore,our approach supports noise reduction and optical image generation,enabling models such as denoising autoencoders,variational autoencoders,and generative adversarial networks.Our results demonstrate that ONN-based systems have the potential to surpass the energy efficiency of traditional electronic systems,enabling real-time,low-power image processing in applications such as medical imaging,autonomous vehicles,and edge computing.展开更多
Optical switch matrices are critical components in data centers,telecommunications,and advanced computing systems,facilitating dynamic and flexible routing of optical signals to support the increasing demands of data ...Optical switch matrices are critical components in data centers,telecommunications,and advanced computing systems,facilitating dynamic and flexible routing of optical signals to support the increasing demands of data transmission.As data traffic escalates exponentially,scalability of these matrices becomes paramount.However,the constrained physical space necessitates high integration density,which poses significant challenges related to switching element size and thermal crosstalk,particularly in thermally driven optical switch matrices.In this paper,we propose a scalable optical switch matrix employing ultra-compact thermally tunable micro-disk resonators(MDRs).At each waveguide crossing,dual MDRs are strategically placed to support multiple direction routings,thereby enabling rearrangeable non-blocking connectivity and increasing input/output(I/O)port density.To mitigate thermal crosstalk between adjacent MDRs,specifically engineered routing waveguides are integrated into the matrix.A proof-of-concept silicon photonic 1×8×2λswitch chip is fabricated and evaluated.With the use of the chip,an optical data transmission is experimentally demonstrated.The proposed switch matrix exhibits strong scalability and significantly reduced thermal crosstalk,showcasing its potential for future optical interconnection networks.展开更多
SOI (silicon-on-insulator) is a new material with a lot of important perform- ances such as large index difference, low transmission loss. Fabrication processes for SOI based optoelectronic devices are compatible with...SOI (silicon-on-insulator) is a new material with a lot of important perform- ances such as large index difference, low transmission loss. Fabrication processes for SOI based optoelectronic devices are compatible with conventional IC processes. Having the potential of OEIC monolithic integration, SOI based optoelectronic devices have shown many good characteristics and become more and more attractive recently. In this paper, the recent progresses of SOI waveguide devices in our research group are presented. By highly effective numerical simulation, the single mode conditions for SOI rib waveguides with rectangular and trapezoidal cross-section were accurately investigated. Using both chemical anisotropic wet etching and plasma dry etching techniques, SOI single mode rib waveguide, MMI coupler, VOA (variable optical attenuator), 2×2 thermal-optical switch were successfully designed and fabricated. Based on these, 4×4 and 8×8 SOI optical waveguide integrated switch matrixes are demonstrated for the first time.展开更多
Traditional one-way imaging methods become invalid when a target object is completely hidden behind scattering media. In this case, it has been much more challenging, since the light wave is distorted twice.To solve t...Traditional one-way imaging methods become invalid when a target object is completely hidden behind scattering media. In this case, it has been much more challenging, since the light wave is distorted twice.To solve this problem, we propose an imaging method, so-called round-trip imaging, based on the optical transmission matrix of the scattering medium. We show that the object can be recovered directly from the distorted output wave, where no scanning is required during the imaging process. We predict that this method might improve the imaging speed and have potential application for real-time imaging.展开更多
There are few experimental results available on film thickness at speeds above 5 m/s and they are almost all based on the optical ball-on-disc test rig.In contrast to the contacts in a rolling bearing,in which the lub...There are few experimental results available on film thickness at speeds above 5 m/s and they are almost all based on the optical ball-on-disc test rig.In contrast to the contacts in a rolling bearing,in which the lubricant in the oil reservoir distributes symmetrically,ball-on-disc contact shows asymmetry of lubricant distribution due to centrifugal effects.In order to closely imitate the contact occurring between the ball and the outer ring of a ball bearing,this study proposes an experimental model based on ball-on-glass ring contact.An optical matrix method is used to analyze the optical system,which is composed of a steel ball-lubricant-chromium-coated glass ring.Based on the optical analysis,the measurement system is improved in order to obtain a high quality interference image,which makes it possible to measure the film thickness at high-speeds conditions.展开更多
The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system...The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system,the mode generator and sorter are the backbone.However,most of the current schemes lack the programmability and universality,which makes the MDM link susceptible to the mode crosstalk and environmental disturbances.In this paper,we propose an intelligent multimode optical communication link using universal mode processing(generation and sorting)chips.The mode processor consists of a programmable 4×4 Mach Zehnder interferometer(MZI)network and can be intelligently configured to generate or sort both quasi linearly polarized(LP)modes and orbital angular momentum(OAM)modes in any desired routing state.We experimentally establish a chip-to-chip MDM communication system.The mode basis can be freely switched between four LP modes and four OAM modes.We also demonstrate the multimode optical communication capability at a data rate of 25 Gbit/s.The proposed scheme shows significant advantages in terms of universality,intelligence,programmability and resistance to mode crosstalk,environmental disturbances,and fabrication errors,demonstrating that the MZI-based reconfigurable mode processor chip has great potential in longdistance chip-to-chip multimode optical communication systems.展开更多
As an indispensable part to compensate for the signal crosstalk in fiber communication systems,conventional digital multi-input multi-output(MIMO)signal processor is facing the challenges of high com-putational comple...As an indispensable part to compensate for the signal crosstalk in fiber communication systems,conventional digital multi-input multi-output(MIMO)signal processor is facing the challenges of high com-putational complexity,high power consumption and relatively low processing speed.The optical MIMOenables the best use of light and has been proposed to remedy this limitation.However,the currently existing optical MIMO methods are all restricted to the spatial di-mension,while the temporal dimension is neglected.Here,an on-chip spatial-temporal descrambler with four channels were devised and its MIMO functions were experimentally verified simultaneously in both spatial and temporal dimensions.The spatial crosstalk of single-channel descrambler and four-channel descrambler is respectively less than-21 dB and-18 dB,and the time delay is simultaneously com-pensated successfully.Moreover,a more universal model extended to mode-dependent loss and gain(MDL)compensation was further de-veloped,which is capable of being cascaded for the real optical trans-mission system.The first attempt at photonic spatial-temporal de-scrambler enriched the varieties of optical MIMO,and the proposed scheme provided a new opportunity for all-optical MIMO signal pro-cessing.展开更多
基金supported by the National Natural Science Foundation of China(6117119761371045+2 种基金61201307)the Shandong Provincial Promotive Research Fund for Excellent Young and Middle-aged Scientists(BS2010DX001)the Shandong Provincial Natural Science Foundation (ZR2011FM005)
文摘Compressive sensing（CS） has emerged as a novel sampling framework which enables sparse signal acquisition and reconstruction with fewer measurements below the Nyquist rate.An important issue for CS is the construction of measurement matrix or sensing matrix.A new deterministic sensing matrix,named as OOC-B,is proposed by exploiting optical orthogonal codes（OOCs）,Bernoulli matrix and Singer structure,which has the entries of 0,＋1 and-1 before normalization.We have proven that the designed deterministic matrix is asymptotically optimal.In addition,the proposed deterministic sensing matrix is applied to direction of arrival（DOA） estimation of narrowband signals by CS arrays（CSA）processing and CS recovery.Theoretical analysis and simulation results show that the proposed sensing matrix has good performance for DOA estimation.It is very effective for simplifying hardware structure and decreasing computational complexity in DOA estimation by CSA processing.Besides,lower root mean square error（RMSE） and bias are obtained in DOA estimation by CS recovery.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB301701)the National High Technology Research and Development Program of China(Grant Nos.2013AA014402+2 种基金2012AA012202and 2015AA016904)the National Natural Science Foundation of China(Grant Nos.61275065 and 61107048)
文摘The first path-independent insertion-loss（PILOSS） strictly non-blocking 4×4 silicon electro–optic switch matrix is reported. The footprint of this switch matrix is only 4.6 mm×1.0 mm. Using single-arm modulation, the crosstalk measured in this test is-13 dB --27 dB. And a maximum crosstalk deterioration of 6d B caused by two-path interference is also found.
基金Supported by the National Natural Science Foundation of China(NSFC 61501396)the Colleges and Universities under the Science and Technology Research Projects of Hebei Province(QN2015021)
文摘Based on a strong inter-diagonal matrix and Taylor series expansions,an oversample reconstruction method was proposed to calibrate the optical micro-scanning error. The technique can obtain regular 2 ×2 microscanning undersampling images from the real irregular undersampling images,and can then obtain a high spatial oversample resolution image. Simulations and experiments show that the proposed technique can reduce optical micro-scanning error and improve the system＇s spatial resolution. The algorithm is simple,fast and has low computational complexity. It can also be applied to other electro-optical imaging systems to improve their spatial resolution and has a widespread application prospect.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0401902 and 2016YFB0402001)Key-Area Research and Development Program of Guang Dong Province,China(Grant No.2019B010926001)。
文摘Phase modulation is a crucial step when the frequency-based wavefront optimization technique is exploited to measure the optical transmission matrix(TM) of a scattering medium. We report a simple but powerful method, direct digital frequency synthesis(DDS) technology to modulate the phase front of the laser and measure the TM. By judiciously modulating the phase front of a He–Ne laser beam, we experimentally generate a high quality focus at any targeted location through a 2 mm thick 120 grit ground glass diffuser, which is commercially used in laser display and laser holographic display for improving brightness uniformity and reducing speckle. The signal to noise ratio(SNR) of the clear round focus is 50 and the size is about 44 μm. Our study will open up new avenues for enhancing light energy delivery to the optical engine in laser TV to lower the power consumption, phase compensation to reduce the speckle noise, and controlling the lasing threshold in random lasers.
基金supported by the National Natural Science Foundation of China(61372069)and the"111"Project(B08038)
文摘In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.
基金supported in part by the National Natural Science Foundation of China （61172051,61302070,61302071,61302072） the Specialized Research Fund for the Doctoral Program of Higher Education（20110042110023） the Fundamental Research Funds for the Central Universities（N110204001, N120804002,N110604008）
文摘Currently,multicast survivability in optical network obtains more attention.This paper focuses on the field of multicast grooming shared protection in green optical network and designs a novel auxiliary graph and a shared matrix to address the survivable multicast resource consumption.This paper also proposes a new heuristic called Green Multicast Grooming algorithm based on spanning path Cross-Shared protection(GMGCSP),in which network reliability,energy efficiency and resource utilization are jointly considered.Simulation results testify that,compared to other algorithms,the proposed GMG-CSP not only has lower blocking probability and higher bandwidth utilization ratio,but also saves more energy.
基金National Natural Science Foundation of China(U22A2080)Project of Fujian Province Major Science and Technology(2020HZ01012)National Key Research and Development Program of China(2018YFA0701800)。
文摘Multiplexing technology serves as an effective approach to increase both information storage and transmission capability.However,when exploring multiplexing methods across various dimensions,the polarization dimension encounters limitations stemming from the finite orthogonal combinations.Given that only two mutually orthogonal polarizations are identifiable on the basic Poincarésphere,this poses a hindrance to polarization modulation.To overcome this challenge,we propose a construction method for the optical polarized orthogonal matrix(OPOM),which is not constrained by the number of orthogonal combinations.Furthermore,we experimentally validate its application in high-dimensional multiplexing of polarization holography.We explore polarization holography technology,capable of recording amplitude,phase,and polarization,for the purpose of recording and selective reconstruction of polarization multi-channels.Our research reveals that,despite identical polarization states,multiple images can be independently manipulated within distinct polarization channels through orthogonal polarization combinations,owing to the orthogonal selectivity among information.
基金supported by the National Research Foundation(NRF)of Korea funded by the Ministry of Science,ICT and Future Planning(MSIP)of Korea(Nos.RS-2021-NR060087 and RS-2024-00353762)。
文摘This study introduces an optical neural network(ONN)-based autoencoder for efficient image processing,utilizing specialized optical matrix-vector multipliers for both encoding and decoding tasks.To address the challenges in efficient decoding,we propose a method that optimizes output processing through scalar multiplications,enhancing performance in generating higher-dimensional outputs.By employing on-system iterative tuning,we mitigate hardware imperfections and noise,progressively improving image reconstruction accuracy to near-digital quality.Furthermore,our approach supports noise reduction and optical image generation,enabling models such as denoising autoencoders,variational autoencoders,and generative adversarial networks.Our results demonstrate that ONN-based systems have the potential to surpass the energy efficiency of traditional electronic systems,enabling real-time,low-power image processing in applications such as medical imaging,autonomous vehicles,and edge computing.
基金National Natural Science Foundation of China(U22A2018,62071042)。
文摘Optical switch matrices are critical components in data centers,telecommunications,and advanced computing systems,facilitating dynamic and flexible routing of optical signals to support the increasing demands of data transmission.As data traffic escalates exponentially,scalability of these matrices becomes paramount.However,the constrained physical space necessitates high integration density,which poses significant challenges related to switching element size and thermal crosstalk,particularly in thermally driven optical switch matrices.In this paper,we propose a scalable optical switch matrix employing ultra-compact thermally tunable micro-disk resonators(MDRs).At each waveguide crossing,dual MDRs are strategically placed to support multiple direction routings,thereby enabling rearrangeable non-blocking connectivity and increasing input/output(I/O)port density.To mitigate thermal crosstalk between adjacent MDRs,specifically engineered routing waveguides are integrated into the matrix.A proof-of-concept silicon photonic 1×8×2λswitch chip is fabricated and evaluated.With the use of the chip,an optical data transmission is experimentally demonstrated.The proposed switch matrix exhibits strong scalability and significantly reduced thermal crosstalk,showcasing its potential for future optical interconnection networks.
基金This work was supported by the National“973"Project of China(Grant No,G2000-03-66)the National“863”Project(Grant No.2002AA3 12060)of the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China(Grant Nos.69896260 and 60336010).
文摘SOI (silicon-on-insulator) is a new material with a lot of important perform- ances such as large index difference, low transmission loss. Fabrication processes for SOI based optoelectronic devices are compatible with conventional IC processes. Having the potential of OEIC monolithic integration, SOI based optoelectronic devices have shown many good characteristics and become more and more attractive recently. In this paper, the recent progresses of SOI waveguide devices in our research group are presented. By highly effective numerical simulation, the single mode conditions for SOI rib waveguides with rectangular and trapezoidal cross-section were accurately investigated. Using both chemical anisotropic wet etching and plasma dry etching techniques, SOI single mode rib waveguide, MMI coupler, VOA (variable optical attenuator), 2×2 thermal-optical switch were successfully designed and fabricated. Based on these, 4×4 and 8×8 SOI optical waveguide integrated switch matrixes are demonstrated for the first time.
基金supported by the National Natural Science Foundation of China(Nos.61535015,61275149,and 61275086)the Special Scientific Research Plan from Education Department of Shaanxi Provincial Government(No.16JK1083)
文摘Traditional one-way imaging methods become invalid when a target object is completely hidden behind scattering media. In this case, it has been much more challenging, since the light wave is distorted twice.To solve this problem, we propose an imaging method, so-called round-trip imaging, based on the optical transmission matrix of the scattering medium. We show that the object can be recovered directly from the distorted output wave, where no scanning is required during the imaging process. We predict that this method might improve the imaging speed and have potential application for real-time imaging.
基金The work was supported by the National Natural Science Foundation of China，the National Key Basic Research (973)Program of China
文摘There are few experimental results available on film thickness at speeds above 5 m/s and they are almost all based on the optical ball-on-disc test rig.In contrast to the contacts in a rolling bearing,in which the lubricant in the oil reservoir distributes symmetrically,ball-on-disc contact shows asymmetry of lubricant distribution due to centrifugal effects.In order to closely imitate the contact occurring between the ball and the outer ring of a ball bearing,this study proposes an experimental model based on ball-on-glass ring contact.An optical matrix method is used to analyze the optical system,which is composed of a steel ball-lubricant-chromium-coated glass ring.Based on the optical analysis,the measurement system is improved in order to obtain a high quality interference image,which makes it possible to measure the film thickness at high-speeds conditions.
基金National Natural Science Foundation of China(62275088,62075075,U21A20511)Innovation Project of Optics Valley Laboratory(Grant No.OVL2021BG001)+1 种基金Research Grants Council,University Grants Committee of Hong Kong SAR under Grant PolyU15301022Knowledge Innovation Program of Wuhan-Basic Research 2023010201010049.
文摘The increasing amount of data exchange requires higher-capacity optical communication links.Mode division multiplexing(MDM)is considered as a promising technology to support the higher data throughput.In an MDM system,the mode generator and sorter are the backbone.However,most of the current schemes lack the programmability and universality,which makes the MDM link susceptible to the mode crosstalk and environmental disturbances.In this paper,we propose an intelligent multimode optical communication link using universal mode processing(generation and sorting)chips.The mode processor consists of a programmable 4×4 Mach Zehnder interferometer(MZI)network and can be intelligently configured to generate or sort both quasi linearly polarized(LP)modes and orbital angular momentum(OAM)modes in any desired routing state.We experimentally establish a chip-to-chip MDM communication system.The mode basis can be freely switched between four LP modes and four OAM modes.We also demonstrate the multimode optical communication capability at a data rate of 25 Gbit/s.The proposed scheme shows significant advantages in terms of universality,intelligence,programmability and resistance to mode crosstalk,environmental disturbances,and fabrication errors,demonstrating that the MZI-based reconfigurable mode processor chip has great potential in longdistance chip-to-chip multimode optical communication systems.
基金National Key Research and Development Program of China(2021YFB2801903,2021YFB2801900)National Natural Science Foundation of China(62075075,U21A20511,62275088)Innovation Project of Optics Valley Laboratory(Grant No.OVL2021BG001).
文摘As an indispensable part to compensate for the signal crosstalk in fiber communication systems,conventional digital multi-input multi-output(MIMO)signal processor is facing the challenges of high com-putational complexity,high power consumption and relatively low processing speed.The optical MIMOenables the best use of light and has been proposed to remedy this limitation.However,the currently existing optical MIMO methods are all restricted to the spatial di-mension,while the temporal dimension is neglected.Here,an on-chip spatial-temporal descrambler with four channels were devised and its MIMO functions were experimentally verified simultaneously in both spatial and temporal dimensions.The spatial crosstalk of single-channel descrambler and four-channel descrambler is respectively less than-21 dB and-18 dB,and the time delay is simultaneously com-pensated successfully.Moreover,a more universal model extended to mode-dependent loss and gain(MDL)compensation was further de-veloped,which is capable of being cascaded for the real optical trans-mission system.The first attempt at photonic spatial-temporal de-scrambler enriched the varieties of optical MIMO,and the proposed scheme provided a new opportunity for all-optical MIMO signal pro-cessing.
