National R&D activities on optical switching networkare introduced. Optical switching network testbedswere established in China including 3T-net andOBS ring and mesh network test-bed with the supportof national &#...National R&D activities on optical switching networkare introduced. Optical switching network testbedswere established in China including 3T-net andOBS ring and mesh network test-bed with the supportof national '863' program. As an importantmodule in OPS network, a novel all-optical serialmulticast mode is discussed.展开更多
A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc...A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc in a model circuit breaker is studied by means of computational fluid dynamics(CFD)simulations and optical emission spectroscopy(OES)in this contribution.Experimental investigations are performed in carbon dioxide(CO2)at absolute filling pressures of 0.1 and 0.5 MPa.CFD simulations are carried out based on a model of the arcing zone including a consistent treatment of the radiation transport and the wall ablation.Carbon ion line radiation is analysed in the experiment using an optical path in the heating channel between the electrodes inside the nozzle system.The pressure value in the arc is estimated based on the line width-intensity dependence.Obtained values correspond to the measured pressure outside the arc.For the temperature profiles,a good agreement within the accuracy of the approaches is observed between the CFD simulations and the results of OES.展开更多
Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable co...Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective,energy-efficient,and transparent data communications.InP integrated photonic circuits offer high-performance amplifiers,switches,modulators,detectors,and de/multiplexers in the same wafer-scale processes.The complexity of these circuits has been transformed as the process technologies have matured,enabling component counts to increase to many hundreds per chip.Active–passive monolithic integration has enabled switching matrices with up to 480 components,connecting 16 inputs to 16 outputs.Integrated switching matrices route data streams of hundreds of gigabits per second.Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections.Wavelength-granularity routing and monitoring is realised inside the chip.In this paper,we review the current status in InP integrated photonics for optical switch matrices,paying particular attention to the additional on-chip functions that become feasible with active component integration.We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective,scalable switching.展开更多
Different multicasting schemes in optical packet switched networks are discussed, including the parallel mode, serial mode, and hybrid mode multicasting schemes. Simulated modeling technique is applied to compare the ...Different multicasting schemes in optical packet switched networks are discussed, including the parallel mode, serial mode, and hybrid mode multicasting schemes. Simulated modeling technique is applied to compare the network-level performance of the three multicasting schemes. A conclusion can be drawn from the results that since the hybrid-mode multicasting scheme can increase the multicast success ratio and reduce the packet retransmission times compared with the other two schemes, it is the best choice for delivering multicasting sessions in the optical packet switched networks.展开更多
Large-scale strictly nonblocking （SNB） and wide-sense nonblocking （WSNB） networks may be infeasible due to their high cost. In contrast, rearrangeable nonblocking （RNB） networks are more scalable because of thei...Large-scale strictly nonblocking （SNB） and wide-sense nonblocking （WSNB） networks may be infeasible due to their high cost. In contrast, rearrangeable nonblocking （RNB） networks are more scalable because of their much lower cost. However, RNB networks are not suitable for circuit switching. In this paper, the concept of virtual nonblockingness is introduced. It is shown that a virtual nonblocking （VNB） network functions like an SNB or WSNB network, but it is constructed with the cost of an RNB network. The results indicate that for large-scale circuit switching applications, it is only needed to build VNB networks.展开更多
Current generalized multi-protocol label switching （GMPLS） standards do not include adequate models for wavelength-switched optical networks （WSON） in recovery mechanisms. In this letter, GMPLS/path computation el...Current generalized multi-protocol label switching （GMPLS） standards do not include adequate models for wavelength-switched optical networks （WSON） in recovery mechanisms. In this letter, GMPLS/path computation element （PCE） extensions are applied for the restoration of the lightpaths disrupted by collision or optical impairment. A reserved deflection routing scheme is proposed to achieve fast restoration. It uses the expanded PCE component to compute and assign the backup paths for lightpath recovery. Numerical results demonstrate that this scheme is effective and low cost.展开更多
基金supported by the NSFC for Distin guished Young Scholars(No.60325104)NSFC (No.90704006)+4 种基金National 973 Program(No.2007CB310705)National 863 Program(No.2006AA01Z238)PCSIRT(No.IRT0609)ISTCP(No.2006DFA11040)111 Project(No.B07005),P.R.China
文摘National R&D activities on optical switching networkare introduced. Optical switching network testbedswere established in China including 3T-net andOBS ring and mesh network test-bed with the supportof national '863' program. As an importantmodule in OPS network, a novel all-optical serialmulticast mode is discussed.
文摘A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc in a model circuit breaker is studied by means of computational fluid dynamics(CFD)simulations and optical emission spectroscopy(OES)in this contribution.Experimental investigations are performed in carbon dioxide(CO2)at absolute filling pressures of 0.1 and 0.5 MPa.CFD simulations are carried out based on a model of the arcing zone including a consistent treatment of the radiation transport and the wall ablation.Carbon ion line radiation is analysed in the experiment using an optical path in the heating channel between the electrodes inside the nozzle system.The pressure value in the arc is estimated based on the line width-intensity dependence.Obtained values correspond to the measured pressure outside the arc.For the temperature profiles,a good agreement within the accuracy of the approaches is observed between the CFD simulations and the results of OES.
基金The work has been supported by the Dutch technology foundation STW.
文摘Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective,energy-efficient,and transparent data communications.InP integrated photonic circuits offer high-performance amplifiers,switches,modulators,detectors,and de/multiplexers in the same wafer-scale processes.The complexity of these circuits has been transformed as the process technologies have matured,enabling component counts to increase to many hundreds per chip.Active–passive monolithic integration has enabled switching matrices with up to 480 components,connecting 16 inputs to 16 outputs.Integrated switching matrices route data streams of hundreds of gigabits per second.Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections.Wavelength-granularity routing and monitoring is realised inside the chip.In this paper,we review the current status in InP integrated photonics for optical switch matrices,paying particular attention to the additional on-chip functions that become feasible with active component integration.We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective,scalable switching.
基金supported by the National "863" Program of China (No.2007AA01Z247)the National"973" Program of China (No.2007CB310705)+3 种基金the National Natural Science Foundation of China (Nos.60772024,60711140087)the Specialized Research Fund for the Doctoral Program of Higher Education from the Ministry of Education of China (No.200800130001)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Different multicasting schemes in optical packet switched networks are discussed, including the parallel mode, serial mode, and hybrid mode multicasting schemes. Simulated modeling technique is applied to compare the network-level performance of the three multicasting schemes. A conclusion can be drawn from the results that since the hybrid-mode multicasting scheme can increase the multicast success ratio and reduce the packet retransmission times compared with the other two schemes, it is the best choice for delivering multicasting sessions in the optical packet switched networks.
文摘Large-scale strictly nonblocking （SNB） and wide-sense nonblocking （WSNB） networks may be infeasible due to their high cost. In contrast, rearrangeable nonblocking （RNB） networks are more scalable because of their much lower cost. However, RNB networks are not suitable for circuit switching. In this paper, the concept of virtual nonblockingness is introduced. It is shown that a virtual nonblocking （VNB） network functions like an SNB or WSNB network, but it is constructed with the cost of an RNB network. The results indicate that for large-scale circuit switching applications, it is only needed to build VNB networks.
基金supported in part by the National"863"Program(No.2007AA01Z252)the National Natural Science Foundation of China(Nos.60772024 and 60711140087)+4 种基金the National"973"Program of China (No.2007CB310705)the Specialized Research Fund for the Doctoral Program of Higher Education of MOE (No.200800130001)the Program for Changjiang Scholars and Innovative Research Team(No.IRT0609)the International S&T Cooperation Program of China(No. 2006DFA11040)the New Century Excellent Talents in University(No.06-0090)
文摘Current generalized multi-protocol label switching （GMPLS） standards do not include adequate models for wavelength-switched optical networks （WSON） in recovery mechanisms. In this letter, GMPLS/path computation element （PCE） extensions are applied for the restoration of the lightpaths disrupted by collision or optical impairment. A reserved deflection routing scheme is proposed to achieve fast restoration. It uses the expanded PCE component to compute and assign the backup paths for lightpath recovery. Numerical results demonstrate that this scheme is effective and low cost.
