Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventiona...Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.展开更多
Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly proces...Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly processes,several bottleneck problems occur in the existing auxiliary assembly technology.First,the traditional LiDARbased assembly technology is often limited by the openness of the manufacturing environment,in which there are blind spots,and continuous online assembly adjustment thus cannot be realized.Second,for assembly of large structures,a single-station LiDAR system cannot achieve complete coverage,which means that a multi-station combination method must be used to acquire the complete three-dimensional data;many more data errors are caused by the transfer between stations than by the measurement accuracy of a single station,which means that the overall system's measurement and adjustment errors are increased greatly.Third,because of the large numbers of structural components contained in a large assembly,the accumulated errors may lead to assembly interference,but the LiDAR-assisted assembly process does not have a feedback perception capability,and thus assembly component loss can easily be caused when assembly interference occurs.Therefore,this paper proposes to combine an optical fiber sensor network with digital twin technology,which will allow the test data from the assembly entity state in the real world to be applied to the"twin"model in the virtual world and thus solve the problems with test openness and data transfer.The problem of station and perception feedback is also addressed and represents the main innovation of this work.The system uses an optical fiber sensor network as a flexible sensing medium to monitor the strain field distribution within a complex area in real time,and then completes real-time parameter adjustment of the virtual assembly based on the distributed data.Complex areas include areas that are laser-unreachable,areas with complex contact surfaces,and areas with large-scale bending deformations.An assembly condition monitoring system is designed based on the optical fiber sensor network,and an assembly condition monitoring algorithm based on multiple physical quantities is proposed.The feasibility of use of the optical fiber sensor network as the real-state parameter acquisition module for the digital twin intelligent assembly system is discussed.The offset of any position in the test area is calculated using the convolutional neural network of a residual module to provide the compensation parameters required for the virtual model of the assembly structure.In the model optimization parameter module,a correction data table is obtained through iterative learning of the algorithm to realize state prediction from the test data.The experiment simulates a largescale structure assembly process,and performs virtual and real mapping for a variety of situations with different assembly errors to enable correction of the digital twin data stream for the assembly process through the optical fiber sensor network.In the plane strain field calibration experiment,the maximum error among the test values for this system is 0.032 mm,and the average error is 0.014 mm.The results show that use of visual calibration can correct the test error to within a very small range.This result is equally applicable to gradient curvature surfaces and freeform surfaces.Statistics show that the average measurement accuracy error for regular surfaces is better than 11.2%,and the average measurement accuracy error for irregular surfaces is better than 14.8%.During simulation of large-scale structure assembly experiments,the average position deviation accuracy is 0.043 mm,which is in line with the designed accuracy.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. Firs...In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness （CASC）, is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit （FF） CASC algorithm and the random-fit （RF） CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.展开更多
The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid...The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid wavelength division multiplexing/time division multiplexing （WDM/TDM） techniques similar to the fiber communication passive optical network （PON）, is proposed. The network topology scheme of a hybrid TDM/WDM/FDM （frequency division multiplexing） three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.展开更多
Optical fiber sensor networks(OFSNs)provide powerful tools for large-scale buildings or long-distance sensing,and they can realize distributed or quasi-distributed measurement of temperature,strain,and other physical ...Optical fiber sensor networks(OFSNs)provide powerful tools for large-scale buildings or long-distance sensing,and they can realize distributed or quasi-distributed measurement of temperature,strain,and other physical quantities.This article provides some optical fiber sensor network technologies based on the white light interference technology.We discuss the key issues in the fiber white light interference network,including the topology structure of white light interferometric fiber sensor network,the node connection components,and evaluation of the maximum number of sensors in the network.A final comment about further development prospects of fiber sensor network is presented.展开更多
A CWDM is proposed for fiber optic communication networks. The OADM is designed based on SOI structure. The scheme for CWDM optical signal protection is presented.
We propose and experimentally validate an optical true time delay beamforming scheme with straightforward integration into hybrid optical/millimeter（mm）-wave access networks. In the proposed approach, the most compl...We propose and experimentally validate an optical true time delay beamforming scheme with straightforward integration into hybrid optical/millimeter（mm）-wave access networks. In the proposed approach, the most complex functions, including the beamforming network, are implemented in a central office, reducing the complexity and cost of remote antenna units. Different cores in a multi-core fiber are used to distribute the modulated signals to high-speed photodetectors acting as heterodyne mixers. The mm-wave carrier frequency is fixed to 50 GHz（VBand）, thereby imposing a progressive delay between antenna elements of a few picoseconds. That true time delay is achieved with an accuracy lower than 1 ps and low phase noise.展开更多
Optical comb filters based on multi-port fused fiber couplers are proposed and numerically analyzed, 3-arm MZI composed by 1×7 fiber splitter and 3×3 fiber coupler, and 2-stage cascaded FIR type MZI interlea...Optical comb filters based on multi-port fused fiber couplers are proposed and numerically analyzed, 3-arm MZI composed by 1×7 fiber splitter and 3×3 fiber coupler, and 2-stage cascaded FIR type MZI interleave filter.展开更多
In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy an...In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy and bypass the optical transmission signal at shortest delay time.展开更多
Crystal optics and fiber grating technology are two of the most important optical fiber device technologies. In this paper, we report several new devices developed in Accelink for WDM networks application.
The stable multicast flow aggregation （MFA） problem in internet protocol （IP） over optical network under the dynamical scenario is studied. Given an optical network topology, there is a set of head ends and access...The stable multicast flow aggregation （MFA） problem in internet protocol （IP） over optical network under the dynamical scenario is studied. Given an optical network topology, there is a set of head ends and access touters attached to the optical network, in which each head end can provide a set of programs （IP multicasting flows） and each access router requests a set of programs, we find a set of stable light-trees to accommodate the optimally aggregated multicast IP flows if the requests of access touters changed dynamically. We introduce a program correlation matrix to describe the preference of end users＇ requests. As the original MFA problem is NP-complete, a heuristic approach, named most correlated program first （MCPF）, is presented and compared with the extended least tree first （ELTF） algorithm which is topology- aware. Simulation results show that MCPF can achieve better performance than ELTF in terms of stability with negligible increment of network resource usage.展开更多
We demonstrate flexible multidimensional modulation formats, polarization multiplexed k-symbol check quad- rature phase shift keying （PM-kSC-QPSK）, based on PM-QPSK constellations for elastic optical networks. The e...We demonstrate flexible multidimensional modulation formats, polarization multiplexed k-symbol check quad- rature phase shift keying （PM-kSC-QPSK）, based on PM-QPSK constellations for elastic optical networks. The experimental results show a significant optical signal noise ratio （OSNR） tolerance improvement for PM-2SC- QPSK and PM-4SC-QPSK over PM-QPSK in both back-to-back and 500 km transmission scenarios at the expense of spectral efficiency reduction. This flexible modulation method can be used ＇in elastic optical networks to provide a trade-off between the spectral efficiency and OSNR tolerance.展开更多
The liquid-core fiber with relatively high refractive index difference between the core and cladding is proven to be bending insensitive. The single mode condition and bending loss of the fiber with a mixture of tolue...The liquid-core fiber with relatively high refractive index difference between the core and cladding is proven to be bending insensitive. The single mode condition and bending loss of the fiber with a mixture of toluene and chloroform as its core material are studied. The results show that the bending loss of this fiber is not only much smaller than the conventional silica single mode fiber but also can be tuned by the temperature and liquid mixture ratio. This kind of fiber may find its potential applications in all-optical network.展开更多
We propose a stable multi-longitudinal Brillouin/semiconductor fiber laser （BSFL） as the upstream source in a bidirectional single-fiber wavelength-division multiplexing-passive optical network （WDM-PON）. The down...We propose a stable multi-longitudinal Brillouin/semiconductor fiber laser （BSFL） as the upstream source in a bidirectional single-fiber wavelength-division multiplexing-passive optical network （WDM-PON）. The downstream wavelength serves as the pump of the BSFL. Brillouin-frequency-shifted （-10.8 GHz） upstream carrier is generated to suppress the Rayleigh backscattering and back reflection-induced crosstalk. The stable multi-longitudinal operation of the BSFL, attributed to the four-wave mixing （FWM） effect in the semiconductor optical amplifier （SOA） reduces the difficulty of generating a stable single-longitudinal fiber laser-based upstream carrier. Bidirectional symmetric transmission at 10 Gb/s over a 12.5-km single mode fiber with less than 2-dB power penalty is demonstrated.展开更多
We present a novel method for providing broadcast signal transmission in a wavelength division multiplexing passive optical network （WDM-PON）. An unmodulated optical carrier for downstream transmission and a pair of...We present a novel method for providing broadcast signal transmission in a wavelength division multiplexing passive optical network （WDM-PON）. An unmodulated optical carrier for downstream transmission and a pair of unmodulated single-side band subcarriers are utilized for broadcast delivery and upstream transmission, respectively. System performance at 2.5-Gb/s down/upstream and 2.5-Gb/s broadcast transmission is also investigated.展开更多
As the wavelength division multiplexing （WDM） technology matures and the demands for bandwidth increase, survivability becomes more and more important in generalized multi-protocol label switching （GMPLS） controll...As the wavelength division multiplexing （WDM） technology matures and the demands for bandwidth increase, survivability becomes more and more important in generalized multi-protocol label switching （GMPLS） controlled intelligent optical networks （IONs）. There are great interests to study the performance of restorability under one certain connection management strategy. And studies in the problem of providing recovery from link failures under two different resource reservation schemes, forward reservation protocols （FRPs） and backward reservation protocols （BRPs）, are presented. They are examined from the point of view of connection blocking probability, restorability and average recovery time. The two different connection management schemes and the survey of different recovery schemes are first presented. The performance of these recovery strategies is analyzed and compared both through theoretical analysis and simulation results. The main stressed idea is that using BRPs gives the best performance in terms of restorability and blocking Drobability in restorable GMPLS networks.展开更多
The loss properties of air-core plastic photonic bandgap fibers are analyzed by multipole method. Despite the relatively large absorption loss of plastics (PMMA), the contribution of material absorption loss can be re...The loss properties of air-core plastic photonic bandgap fibers are analyzed by multipole method. Despite the relatively large absorption loss of plastics (PMMA), the contribution of material absorption loss can be reduced significantly through appropriate selection of operating wavelength, number of cladding air-hole rings, radius of air-core, and position of photonic band gap. The transmission loss in this type of fiber can be decreased by an order of magnitude in comparison with that of conventional plastic optical fiber.展开更多
This paper investigates the problem of dynamic protected lightpath services provisioning in optical mesh networks employing wavelength division multiplexing (WDM). A variety of schemes for dynamic protected services p...This paper investigates the problem of dynamic protected lightpath services provisioning in optical mesh networks employing wavelength division multiplexing (WDM). A variety of schemes for dynamic protected services provisioning have been proposed, supporting a range of tradeoffs among restoration speed, capacity efficiency, and scalability. In this paper, we propose a novel scheme, called p-cycles-based maximum protected working capacity envelope (PC-MPWCE), which can offer an attractive combination of features: ring-like speed, mesh-like capacity efficiency, and good scalability. To evaluate the performance of PC-MPWCE, we compare it via simulation with 1 + 1 automatic protection switching (APS) and two well-known shared backup path protection (SBPP) on NSFNET. Our simulation results show that PC-MPWCE can achieve much better blocking performance than 1 + 1 APS, and perform the similar blocking performance and capacity efficiency as SBPP.展开更多
A novel wavelength assignment scheme called the wavelength pre-assignment collision schedule （WPCS） is proposed for wavelength-routed networks. The WPCS pre-assigns the wavelength at the forward detection phase, and...A novel wavelength assignment scheme called the wavelength pre-assignment collision schedule （WPCS） is proposed for wavelength-routed networks. The WPCS pre-assigns the wavelength at the forward detection phase, and schedules the potential collision by priority. The potential collision is scheduled at the forward detection phase and the blocking of the wavelength assignment is reduced. Simulation is conducted with several other existing schemes. The numerical results show that WPCS performs better than other schemes in blocking probability under various traffic conditions.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2020YFC2200103)the Shandong Provincial Natural Science Foundation(Grant Nos.ZR2022LLZ006 and ZR2022LLZ011)+1 种基金the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0300904 and 2021ZD0300903)the Key R&D Plan of Shandong Province(Grant No.2023CXPT105)。
文摘Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.
基金supported by the National Science Foundation of China(Theoretical Model and Experimental Research on the Novel FBG Sensing System based on the Fusion Algorithm,No.61703056)the Jilin Province Science and Technology Development Plan Project(No.20190103154JH)。
文摘Intelligent assembly of large-scale,complex structures using an intelligent manufacturing platform represents the future development direction for industrial manufacturing.During large-scale structural assembly processes,several bottleneck problems occur in the existing auxiliary assembly technology.First,the traditional LiDARbased assembly technology is often limited by the openness of the manufacturing environment,in which there are blind spots,and continuous online assembly adjustment thus cannot be realized.Second,for assembly of large structures,a single-station LiDAR system cannot achieve complete coverage,which means that a multi-station combination method must be used to acquire the complete three-dimensional data;many more data errors are caused by the transfer between stations than by the measurement accuracy of a single station,which means that the overall system's measurement and adjustment errors are increased greatly.Third,because of the large numbers of structural components contained in a large assembly,the accumulated errors may lead to assembly interference,but the LiDAR-assisted assembly process does not have a feedback perception capability,and thus assembly component loss can easily be caused when assembly interference occurs.Therefore,this paper proposes to combine an optical fiber sensor network with digital twin technology,which will allow the test data from the assembly entity state in the real world to be applied to the"twin"model in the virtual world and thus solve the problems with test openness and data transfer.The problem of station and perception feedback is also addressed and represents the main innovation of this work.The system uses an optical fiber sensor network as a flexible sensing medium to monitor the strain field distribution within a complex area in real time,and then completes real-time parameter adjustment of the virtual assembly based on the distributed data.Complex areas include areas that are laser-unreachable,areas with complex contact surfaces,and areas with large-scale bending deformations.An assembly condition monitoring system is designed based on the optical fiber sensor network,and an assembly condition monitoring algorithm based on multiple physical quantities is proposed.The feasibility of use of the optical fiber sensor network as the real-state parameter acquisition module for the digital twin intelligent assembly system is discussed.The offset of any position in the test area is calculated using the convolutional neural network of a residual module to provide the compensation parameters required for the virtual model of the assembly structure.In the model optimization parameter module,a correction data table is obtained through iterative learning of the algorithm to realize state prediction from the test data.The experiment simulates a largescale structure assembly process,and performs virtual and real mapping for a variety of situations with different assembly errors to enable correction of the digital twin data stream for the assembly process through the optical fiber sensor network.In the plane strain field calibration experiment,the maximum error among the test values for this system is 0.032 mm,and the average error is 0.014 mm.The results show that use of visual calibration can correct the test error to within a very small range.This result is equally applicable to gradient curvature surfaces and freeform surfaces.Statistics show that the average measurement accuracy error for regular surfaces is better than 11.2%,and the average measurement accuracy error for irregular surfaces is better than 14.8%.During simulation of large-scale structure assembly experiments,the average position deviation accuracy is 0.043 mm,which is in line with the designed accuracy.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
基金supported by the National Natural Science Foundation of China(Nos.61571058 and 61501049)the National 863 Project of China(No.2015AA015503)+2 种基金the State Key Laboratory of Information Photonics and Optical Communications(Nos.IPOC2014ZZ03 and IPOC2015ZT01)the Chinese Scholarship Council(CSC),BUPT Excellent Ph.D.Students Foundation(No.CX2015307)the NSF Project(No.CNS-1302645).
文摘In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment （CA-RCSA） algorithms for spatial division multiplexing enabled elastic optical networks （SDM-EONs） with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness （CASC）, is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit （FF） CASC algorithm and the random-fit （RF） CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.
基金These works are supported by a grant from the Sub-Project of the Major Program of the National Natural Science Foundation of China （No. 61290315）, the National Natural Science Foundation of China （No. 61275083, 61275004, and 61404056）, the National Key Foundation of Exploring Scientific Instrument of China （No. 2013YQ16048707）, and the Fundamental Research Funds for the Central Universities （HUST： No. 2014CG002, and 2014QNRC005）. Much appreciation should be given to the students, Zhinlin Xu, Yiyang Luo, Fan Ai, Wei Yang, Enci Chen, Shun Wang ,Shui Zhao, Li Liu, Hao Liao, Xin Fu, Shun Wang, Wei Yang, Wang Yang, and Mingren Su.
文摘The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid wavelength division multiplexing/time division multiplexing （WDM/TDM） techniques similar to the fiber communication passive optical network （PON）, is proposed. The network topology scheme of a hybrid TDM/WDM/FDM （frequency division multiplexing） three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.
文摘Optical fiber sensor networks(OFSNs)provide powerful tools for large-scale buildings or long-distance sensing,and they can realize distributed or quasi-distributed measurement of temperature,strain,and other physical quantities.This article provides some optical fiber sensor network technologies based on the white light interference technology.We discuss the key issues in the fiber white light interference network,including the topology structure of white light interferometric fiber sensor network,the node connection components,and evaluation of the maximum number of sensors in the network.A final comment about further development prospects of fiber sensor network is presented.
文摘A CWDM is proposed for fiber optic communication networks. The OADM is designed based on SOI structure. The scheme for CWDM optical signal protection is presented.
基金founded by H2020 ITN CELTA under Grant No.675683 of Call:H2020-MSCA-ITN-2015
文摘We propose and experimentally validate an optical true time delay beamforming scheme with straightforward integration into hybrid optical/millimeter（mm）-wave access networks. In the proposed approach, the most complex functions, including the beamforming network, are implemented in a central office, reducing the complexity and cost of remote antenna units. Different cores in a multi-core fiber are used to distribute the modulated signals to high-speed photodetectors acting as heterodyne mixers. The mm-wave carrier frequency is fixed to 50 GHz（VBand）, thereby imposing a progressive delay between antenna elements of a few picoseconds. That true time delay is achieved with an accuracy lower than 1 ps and low phase noise.
文摘Optical comb filters based on multi-port fused fiber couplers are proposed and numerically analyzed, 3-arm MZI composed by 1×7 fiber splitter and 3×3 fiber coupler, and 2-stage cascaded FIR type MZI interleave filter.
文摘In this paper, we study the protection strategies of domestic optical fiber networks in Taiwan. Delay time experiment of two one-link failed cases are also reported and compared. We can get best protection strategy and bypass the optical transmission signal at shortest delay time.
文摘Crystal optics and fiber grating technology are two of the most important optical fiber device technologies. In this paper, we report several new devices developed in Accelink for WDM networks application.
基金the National Natural Science Foundation of China (No.60502004) and the"863"Program of China.
文摘The stable multicast flow aggregation （MFA） problem in internet protocol （IP） over optical network under the dynamical scenario is studied. Given an optical network topology, there is a set of head ends and access touters attached to the optical network, in which each head end can provide a set of programs （IP multicasting flows） and each access router requests a set of programs, we find a set of stable light-trees to accommodate the optimally aggregated multicast IP flows if the requests of access touters changed dynamically. We introduce a program correlation matrix to describe the preference of end users＇ requests. As the original MFA problem is NP-complete, a heuristic approach, named most correlated program first （MCPF）, is presented and compared with the extended least tree first （ELTF） algorithm which is topology- aware. Simulation results show that MCPF can achieve better performance than ELTF in terms of stability with negligible increment of network resource usage.
基金supported by the National Natural Science Foundation of China(No.61571061)the Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),China
文摘We demonstrate flexible multidimensional modulation formats, polarization multiplexed k-symbol check quad- rature phase shift keying （PM-kSC-QPSK）, based on PM-QPSK constellations for elastic optical networks. The experimental results show a significant optical signal noise ratio （OSNR） tolerance improvement for PM-2SC- QPSK and PM-4SC-QPSK over PM-QPSK in both back-to-back and 500 km transmission scenarios at the expense of spectral efficiency reduction. This flexible modulation method can be used ＇in elastic optical networks to provide a trade-off between the spectral efficiency and OSNR tolerance.
基金supported by the National Natural Science Foundation of China(No.10874119)the National"973"Program of China(No.2007CB307000)the Shanghai Leading Academic Discipline Project (No.B201)
文摘The liquid-core fiber with relatively high refractive index difference between the core and cladding is proven to be bending insensitive. The single mode condition and bending loss of the fiber with a mixture of toluene and chloroform as its core material are studied. The results show that the bending loss of this fiber is not only much smaller than the conventional silica single mode fiber but also can be tuned by the temperature and liquid mixture ratio. This kind of fiber may find its potential applications in all-optical network.
基金supported by the National "973" Program of China (Nos. 2010CB328204 and 2010CB328205)the Nature Natural Science Foundation of China (Nos.61007041,61090393,and 60825103)+1 种基金the National 863 Program of Chinathe Program of Shanghai Subject Chief Scientist (No. 09XD1402200)
文摘We propose a stable multi-longitudinal Brillouin/semiconductor fiber laser （BSFL） as the upstream source in a bidirectional single-fiber wavelength-division multiplexing-passive optical network （WDM-PON）. The downstream wavelength serves as the pump of the BSFL. Brillouin-frequency-shifted （-10.8 GHz） upstream carrier is generated to suppress the Rayleigh backscattering and back reflection-induced crosstalk. The stable multi-longitudinal operation of the BSFL, attributed to the four-wave mixing （FWM） effect in the semiconductor optical amplifier （SOA） reduces the difficulty of generating a stable single-longitudinal fiber laser-based upstream carrier. Bidirectional symmetric transmission at 10 Gb/s over a 12.5-km single mode fiber with less than 2-dB power penalty is demonstrated.
基金supported by the Shanghai Leading Academic Discipline Project and Science and Technology Commission of Shanghai Municipality (STCSM) under Grant Nos. S30108 and 08DZ2231100
文摘We present a novel method for providing broadcast signal transmission in a wavelength division multiplexing passive optical network （WDM-PON）. An unmodulated optical carrier for downstream transmission and a pair of unmodulated single-side band subcarriers are utilized for broadcast delivery and upstream transmission, respectively. System performance at 2.5-Gb/s down/upstream and 2.5-Gb/s broadcast transmission is also investigated.
基金This work was jointly supported by the National Science Fund for Distinguished Young Scholars (No. 60325104) the National Natural Science Foundation of China (No. 60572021)the SRFDP of MOE (No. 20040013001).
文摘As the wavelength division multiplexing （WDM） technology matures and the demands for bandwidth increase, survivability becomes more and more important in generalized multi-protocol label switching （GMPLS） controlled intelligent optical networks （IONs）. There are great interests to study the performance of restorability under one certain connection management strategy. And studies in the problem of providing recovery from link failures under two different resource reservation schemes, forward reservation protocols （FRPs） and backward reservation protocols （BRPs）, are presented. They are examined from the point of view of connection blocking probability, restorability and average recovery time. The two different connection management schemes and the survey of different recovery schemes are first presented. The performance of these recovery strategies is analyzed and compared both through theoretical analysis and simulation results. The main stressed idea is that using BRPs gives the best performance in terms of restorability and blocking Drobability in restorable GMPLS networks.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 60444003. T.Guan's e-mail address is guanrichy@163.com.
文摘The loss properties of air-core plastic photonic bandgap fibers are analyzed by multipole method. Despite the relatively large absorption loss of plastics (PMMA), the contribution of material absorption loss can be reduced significantly through appropriate selection of operating wavelength, number of cladding air-hole rings, radius of air-core, and position of photonic band gap. The transmission loss in this type of fiber can be decreased by an order of magnitude in comparison with that of conventional plastic optical fiber.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 69990540 and 90304002.
文摘This paper investigates the problem of dynamic protected lightpath services provisioning in optical mesh networks employing wavelength division multiplexing (WDM). A variety of schemes for dynamic protected services provisioning have been proposed, supporting a range of tradeoffs among restoration speed, capacity efficiency, and scalability. In this paper, we propose a novel scheme, called p-cycles-based maximum protected working capacity envelope (PC-MPWCE), which can offer an attractive combination of features: ring-like speed, mesh-like capacity efficiency, and good scalability. To evaluate the performance of PC-MPWCE, we compare it via simulation with 1 + 1 automatic protection switching (APS) and two well-known shared backup path protection (SBPP) on NSFNET. Our simulation results show that PC-MPWCE can achieve much better blocking performance than 1 + 1 APS, and perform the similar blocking performance and capacity efficiency as SBPP.
基金supported in part by the National"863" Program of China (No.2007AA01Z252)the National "973" Program of China (No.2007CB310705)+3 种基金the National Natural Science Foundation of China (No.60711140087)the Program for New Century Excellent Talents in University (No.06-0090)the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT0609)the International S & T Cooperation Program of China (No.2006DFA11040)
文摘A novel wavelength assignment scheme called the wavelength pre-assignment collision schedule （WPCS） is proposed for wavelength-routed networks. The WPCS pre-assigns the wavelength at the forward detection phase, and schedules the potential collision by priority. The potential collision is scheduled at the forward detection phase and the blocking of the wavelength assignment is reduced. Simulation is conducted with several other existing schemes. The numerical results show that WPCS performs better than other schemes in blocking probability under various traffic conditions.
