Presentation on theme: "Razali Ngah and Z Ghassemlooy Optical Communications Research Group"— Presentation transcript:
1 Razali Ngah and Z Ghassemlooy Optical Communications Research Group Sheffield Hallam UniversitySimulation of an All Optical Time Division Multiplexing Router EmployingTOADsRazali Ngah and Z GhassemlooyOptical Communications Research GroupSchool of Engineering
2 Contents 1. Introduction 2. OTDM Communication System 3. OTDM Packet Format4. All optical switching5. OTDM Router Using TOADs6. Simulation Results and DiscussionsConclusions8. Further worksSheffield Hallam University2
4 Introduction Multiplexing Techniques to extend a transmission capacity OTDM vs. WDMOTDMWDMSingle wavelengthMultiple wavelengthHigh bit rate (up to 640Gb/s)Lower bit rate (2.5 – 100Gb/s)Immature technologyReaching an advanced stage of developmentChromatic dispersion & timing jitterFWM, SRS & XPMOTDM can provide users with better throughput delay performance, faster single-channel access times for high-data-rate end users
5 OTDM Communication System 10 Gbps is commercially availableThere are two types:-Bit Interleaved TDM-Slotted (packet) TDM
6 OTDM Packet Format Format of OTDM packet Multiplexing of Clock Pulse (Frame Sync.)AddressPayloadFormat of OTDM packetMultiplexing of Clock PulseSpace Division MultiplexingWavelength Division MultiplexingOrthogonal PolarizationIntensity Division MultiplexingTime Division MultiplexingCont.Sheffield Hallam University
7 Space division multiplexing OTDM Packet FormatSpace division multiplexing-The clock is carried on by a separate transmission fibre from the data packets-Problems: (i) time varying differential delay between the clock and data, and (ii) the cost of installing a separate clock fibre for each network node in new installation is not practical for wide area networksCont.Sheffield Hallam University
8 -Different wavelengths are allocated to clock and payload OTDM Packet FormatWavelength division multiplexing-Different wavelengths are allocated to clock and payload-Problems: Only practical for predetermined path lengths between nodes in single hop networks.The relative delay between the clock and data will be random in asynchronous packet-switched since the optical path length through which a packet travels is non-deterministicOrthogonal Polarization-An orthogonally polarized clock pulse is used-Problem: Difficult to maintain the correct polarization throughout the systemCont.Sheffield Hallam University
9 Intensity Division Multiplexing OTDM Packet FormatIntensity Division Multiplexing-Higher intensity for the optical clock pulse is used to differentiate it from the data-Problem: The clock pulse amplitude and its position become difficult to maintain in long distance transmissionTime Division Multiplexing-Self-synchronization approach, the clock is located at the start of the packetCont.Sheffield Hallam University
10 a). Asymmetric Terahertz Optical Demultiplexer (TOAD) All Optical Switchinga). Asymmetric Terahertz Optical Demultiplexer (TOAD)b). Mach-Zehnders interferometer (MZI)c). Ultrafast nonlinear interferometer (UNI)- Optical control pulse is used to change SOA’s gain and refractive indexSheffield Hallam University
11 Asymmetric Terahertz Optical Demultiplexer (TOAD) Sheffield Hallam University
12 All Optical Router Using TOADs Cont.Sheffield Hallam University5
13 All Optical Router Using TOADs Sheffield Hallam University
14 Simulation Results and Discussion The model was simulated using Virtual Photonics (VPI) simulation packageSimulation parameters:Cont.
15 Simulation Results and Discussion - OTDM packetCont.
16 Simulation Results and Discussion Extracted Clock SignalTransmitted Output of TOAD1Cont.
17 Simulation Results and Discussion Reflected Output TOAD2(Address bit)Transmitted output of TOAD2(Payload)Cont.
18 Simulation Results and Discussion Payload at Port 2 of TOAD3
19 ConclusionsA node model for an OTDM router (1X2) for asynchronous packet routing is presented-The switching devices employed for clock recovery and payload routing are carried out in optical domain using TOADs-Simulation results demonstrate that clock recovery, address recognition and payload routing has been achieved successfullySheffield Hallam University30
20 Further works To simulate multiple input and output networks Crosstalk and noise analysis for multiple input and output networksSheffield Hallam University31