Optical switching based on the manipulation of microparticles in a colloidal liquid using strong scattering force

This paper demonstrates the realization of an optical switch by optically manipulating a large number of polystyrene spheres contained in a capillary. The strong scattering force exerted on polystyrene spheres with a large diameter of 4.3 μm is employed to realize the switching operation. A transparent window is opened for the signal light when the polystyrene spheres originally located at the beam centre are driven out of the beam region by the strong scattering force induced by the control light. The switching dynamics under different incident powers is investigated and compared with that observed in the optical switch based on the formation of optical matter. It is found that a large extinction ratio of - 30 dB and fast switching-on and switching-off times can be achieved in this type of switch.

Optimization of Key Parameters in 622-Mb/s Amplitude Shift Keying Labeled 40-Gb/s Return to Zero Differential Phase Shift Keying Optical Switching Network

Optimized are the label extinction ratio and dispersion compensation of an optical label switching transmission system,which employs 40-Gb/s return to zero differential phase shift keying(RZ-DPSK)payload labeled with 622-Mb/s amplitude shift keying(ASK)control data.In our scheme,the receiver sensitivities of payload and label achieves-27.8dBm and-33.5dBm,respectively.After transmitted over 40km,60km and 80km single mode fiber(SMF)(with dispersion compensation)respectively,the payload can be recovered with no power penalty,while the label can be recovered with less than 2dB penalty.

Fabrication of high-quality colloidal photonic crystals with sharp band edges for ultrafast all-optical switching

Application of the pressure controlled isothermal heating vertical deposition method to the fabrication of colloidal photonic crystals is systematically investigated in this paper. The fabricated samples are characterized by scanning electron microscope and transmission spectrum. High-quality samples with large transmissions in the pass bands and the sharp band edges are obtained and the optimum growth condition is determined. For the best sample, the transmission in the pass bands approaches 0.9 while that in the band gap reaches 0.1. More importantly, the maximum differential transmission as high as 0.1/nm is achieved. In addition, it is found that the number of stacking layers does not increase linearly with concentration of PS spheres in a solution, and a gradual saturation occurs when the concentration of PS spheres exceeds 1.5 wt.%. The uniformity of the fabricated samples is examined by transmission measurements on areas with different sizes. Finally, the tolerance of the fabricated samples to baking was studied.

Orbital-angular-momentum-based reconfigurable optical switching and routing

Orbital angular momentum(OAM) has gained interest due to its potential to increase capacity in optical communication systems as well as an additional domain for reconfigurable networks. This is due to the following:(i) coaxially propagated OAM beams with different charges are mutually orthogonal,(ii) OAM beams can be efficiently multiplexed and demultiplexed, and(iii) OAM charges can be efficiently manipulated. Therefore, multiple data-carrying OAM beams could have the potential capability for reconfigurable optical switching and routing. In this paper, we discuss work involving reconfigurable OAM-based optical add/drop multiplexing, space switching,polarization switching, channel hopping, and multicasting.

MEMS Torsion-Mirror Actuators for Optical Switching or Attenuating Applications

Novel MEMS torsion-mirror actuators with monolithically integrated fiber self-holding structures are fabricated, and investigated experimentally and theoretically. Their electromechanical and optical characteristics are acceptable for optical switching or attenuating applications.

Optimizing Fiber Topologies for WDM Optical Networks Based on Multi-Granularity Optical Switching Technology

For the quality of service （QoS） and fairness considerations, the hop counts of various lightpaths in a wavelength division multiplexing （WDM） optical network should be short and compact. The development of multi-granularity optical switching technology has made it possible to construct various fiber topologies over a fixed physical topology. This paper describes a fiber topology design （FTD） problem, which minimizes the maximum number of required fibers in the physical links for a maximum lightpath hop count in the fiber topology. After the formular description for the FTD problem, a method was given to obtain the lower bound on the maximum number of required fibers. For large or moderate scale networks, three heuristic algorithms are given to efficiently solve the FTD problem. This study gives a new way to optimize the resource configuration performance in WDM optical networks at the topology level and proves its effectiveness via both analyses and numerical experiments.

ATM Optical Switching Technology

2.5 Gbit/s ATM optical switching experimental system has been achieved for the first time in P.R.China.This poper describes the architecture of the ATM optical switching system.and gives some key technologies forrealization,e.g. photonic switching matrix, header identification, etc. In addition, the performance, analysis andexperimental results are given.

Transmission Mechanism Based on Burst Filling in Hybrid Optical Burst/Circuit Switching Networks

Hybrid optical switching networks make full use of the advantages of Optical Circuit Switching(OCS)and Optical Burst Switching(OBS).In parallel hybrid optical switching networks,edge nodes choose a switching mode for traffic and no longer change.The inflexible decision making of the traffic transfer mode leads to low resource utilization when the arrival rate of the OCS traffic is lower than the capacity of the light path.In this paper,a new transmission scheme is proposed to improve resource utilization for hybrid optical switching networks.When the traffic arrival rate of the light path is lower than the transmission rate of the light path,the OCS traffic flow is reshaped at the edge nodes to generate a series of voids.Then,several message packets are sent along the light path to inform the core nodes of the voids of the light paths that represent the unused bandwidth resources.To improve the resource utilization,the voids can be filled with data bursts by core nodes.The simulation results show that the new scheme can effectively reduce the burst loss rate and improve the link utilization of the hybrid optical switching network on the premise of a providing service quality guarantee for OCS traffic.

Optical Switching and Digital Signal Amplification Using an Optical Fiber Grating OBD

It is proposed that an optical fiber grating bistability device may be used for an all optical switching or an all optical digital signal amplifier with low power and high speed. The principle, characteristic and paremeter are analysed, and some design ideas are given.

Suspended twin-core f iber for optical switching

A kind of novel fiber, comprising two fiber cores which are suspended in air inside the outer cladding via a central thin membrane ,is proposed for optical switching application. When a hydrostatic pressure applied on the optical fiber, the pressure-induced refractive index change of the two fiber cores will contribute to the periodical change of the intensity of guided light in the fiber core. The mode coupling of two cores under different hydrostatic pressure and influences of each structure parameter of the proposed fiber on the switching nressure have been numerically invo.stigated.

Investigation of the influence of key parameters on system performance in all-optical label switching based on FSK/ASK orthogonal modulation format

The transmission characteristics of the optical label switching system based on the FSK/ASK orthogonal modulation format is investigated. The factors that affect the transmission performance, such as the FSK tone space, dispersion compensation and coupler split ratio, are studied by numerical simulation. The proposed scheme is also experimentally demonstrated with a transmission of 155 Mbit/s FSK label combined with 10 Gbit/s ASK payload.

Performance analysis of optical burst switching node with limited wavelength conversion capabilities

The systematical and scalable frameworks were provided for estimating the blocking probabilities under asynchronous traffic in optical burst switching(OBS) nodes with limited wavelength conversion capability(LWCC) . The relevant system architectures of limited range and limited number of wavelength converters(WCs) deployed by a share-per-fiber(SPF) mode were developed,and the novel theoretical analysis of node blocking probability was derived by combining the calculation of discouraged arrival rate in a birth-death process and two-dimensional Markov chain model of SPF. The simulation results on single node performance verify the accuracy and effectiveness of the analysis models. Under most scenarios,it is difficult to distinguish the plots generated by the analysis and simulation. As the conversion degree increases,the accuracy of the analysis model worsens slightly. However,the utmost error on burst loss probability is far less than one order of magnitude and hence,still allows for an accurate estimate. Some results are of actual significance to the construction of next-generation commercial OBS backbones.

Design and Simulation of Routing-switching Protocol Based on Optical Switch Array

An optical routing-switching technology based on optical switch array is proposed.The characteristics of the blocking and nonblocking networks are analyzed and compared,odd-even sorting network is used to realize optical routing-switching,relative routing-switching protocol is designed.Simulation test under load shows that it can reduce a blocking effectively and enhance an efficiency of switching.Further,it can transfer the processing and switching within parallel computer from electric domain to optical domain. It can make parallel computer coordinating computing and processing at much more higher speed, storing and transmitting even more efficiently.

QoS aware routing and wavelength allocation in optical burst switching networks using differential evolution optimization

The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.

Study of Crosstalk Property in an Optical Packet Switching Node

The effect of queuing delay of output buffer on the crosstalk property in optical packet switching nodes is investigated. The relationship between crosstalk and buffer length is obtained. From the calculation and simulation results, it is concluded that the crosstalk power penalty predominantly depends on the buffer length, the longer the buffer, the greater the penalty, as well as the random range of the penalty. While comparing with the effect of queuing delay, the effect of random routing path delay takes very little proportion in the total power penalty.

Simulation of the Physical Performance of Optical Packet Switching Nodes

A graphical and visual simulation system for the study of optical packet switching (OPS) nodes is accomplished. With the simulation system, the effect on physical performance-bit error rate (BER) due to a variety of factors such as the crosstalk parameters of OPS nodes, number of cascaded OPS nodes, length of optical output buffer, traffic load and fluctuation of amplitude of optical signals are evaluated. Reliability of the simulation system is proved by the analytical results obtained in all the above cases.

Study of Token Generation for Burst Traffic Shaping in Optical Burst Switching Networks

Traffic shaping is one of important control operation to guarantee the Quality of Service (QoS) in optical burst switching (OBS) networks. The efficiency of traffic shaping is mainly determined by token generation method. In this paper, token generation methods of traffic shaping are evaluated by using three kinds of probability distribution, and are analyzed in terms of burst blocking probability, through-put and correlation by simulation. The simulation results show that the token generation methods decrease the burst correlation of Label Switched Paths (LSPs), and solve traffic congestion as well. The different burst arrival processes have small impact on the blocking probability for OBS net works. Key words optical burst switching - traffic shaping - token generation - quality of service CLC number TP 929.11 Foundation item: Supported by the National Natural Science Foundation of China (60132030) and the Korea Science and Engineering Foundation (KOSEF) through OIRC ProjectBiography: Tang Wan (1974-), female, Ph. D candidate, research direction: contention resolution and routing mechanism in OBS networks.

Contention avoidance using dual-fuzzy assembly threshold algorithm in optical burst switching networks

To avoid burst contention efficiently,on the basis of feedback-based source flow-rate control(SFC) strategy,a novel fuzzy-control-based assembly algorithm,called dual-fuzzy assembly threshold(DFAT),is proposed in an optical burst switching network.In our algorithm,according to the variations of burst assembly period and the interarrival of burst control packet,the traffic states of edge-switching nodes and core-switching nodes are first obtained.Then,the assembly threshold of bursts is set dynamically in order to operate the source traffic management from the information of traffic states.The performance of DFAT algorithm on burst loss probability is evaluated,and simulation results show that,compared with conventional assembly algorithms,the proposed scheme can constrain the birth of burst contention efficiently,when being a heavy load state of network.

A NEW SCHEDULING ALGORITHM TO PROVIDE PROPORTIONAL QOS IN OPTICAL BURST SWITCHING NETWORKS

A new scheduling algorithm, which aims to provide proportional and controllable QoS (Quality of Service) in terms of burst loss probability for OBS (Optical Burst Switching) networks, is proposed on the ba- sis of a survey of QoS schemes in current OBS networks. With simulations, performance analysis and com- parisons are carried out in detail. The results show that, in the proposed scheme, burst loss probabilities are proportional to the given factors and the control of QoS performance can be achieved with better performance. This scheme will be beneficial to the OBS network management and the tariff policy making.

A novel data channel fault detection mechanism in optical burst switching networks

Fault detection in optical burst switching （OBS） networks will be a challenging task in the future. A novel mechanism based on probe burst （PB） and a new key concept is proposed to detect faults of OBS networks by sampling the health of data channels, which solve the difficulty of optical monitoring schemes while keeps the transparency of data network to Internet protocol （IP） packets. It takes full advantage of the characteristics of OBS, including architecture and signalling scheme, and introduces the excellent performances of single-hop-test used in electrical communication networks into OBS environment while avoids the shortcoming that any optical burst must undergo an optical-electric-optical （OEO） conversion. Well designed PB can provide exact criterion for judging whether protection/restoration should be excuted according to hard or soft fault identification.