1 SUCCESS-DWA: A Highly Scalable and Cost-Effective Optical Access Network Speaker ： Tse-Hsien Lin Teacher ： Ho-Ting Wu Date ：

2 Outline Overview SUCCESS-DWA PON Architecture  Stanford University Access – Dynamic Wavelength Allocation The Upstream Scenario Performance Wavelength Plan Conclusions

3 Overview Passive Optical Network (PON) The Time-Division Multiplexed (TDM) PON The Wavelength-Division Multiplexed (WDM) PON Arrayed Waveguide Grating (AWG)

4 Passive Optical Network In a PON, all components between the end users and the central office (CO) are passive

5 The TDM PON In a TDM PON, end users share the bandwidth in time domain In the CO, an optical line terminal (OLT) transmits the downstream traffic to the end users and manages the upstream traffic flows from the end users

6 The TDM PON Downstream  The traffic is broadcast in nature  Each Optical network unit (ONU) receives a copy of the downstream data, extracts only the traffic targeting itself Upstream  Traffic from the ONUs to the OLT is centrally scheduled by the OLT

7 The TDM PON

8 The WDM PON What’s is WDM  At the same time, The fiber can carry Independent data streams on different wavelengths WDM PONs create point-to-point links between the CO and end user, no sharing is needed

9 The WDM PON A straightforward approach for increasing capacity is to assign different wavelengths to each user for down/upstream transmissions When a user is idle, the corresponding transceiver in the CO is also idle and cannot be used to support other users Disadvantage  High Cost  Waste Bandwidth

10 Arrayed Waveguide Grating The AWG is a wavelength-routing device Every second wavelength is routed to the same output port This period of the wavelength response is called free spectral range (FSR)

11 SUCCESS-DWA PON Architecture TL = Tunable laserCH X = Thin-film WDM filter

12 Downstream Two TLs must not access the same ONU simultaneously The AWG does allow all TLs to simultaneously transmit on the same wavelength All TLs share the load, shifting bandwidth back and forth across the separate physical PONs --DWA

13 Functional diagrams of the OLT and ONU

14 The Upstream Scenario Each user is equipped with a fixed-wavelength transmitter that corresponds to the upstream group

15 The Upstream Scenario Additionally, upstream and downstream AWGs pass completely different wavelengths and require different channel spacings Only one Photodetector (PD) and its corresponding receiver module are activated in the initial deployment

16 Performance We compare the performance of a four-TL SUCCESS-DWA PON to four TDM PONs Both TDM and SUCCESS-DWA PONs are subject to the exact same traffic patterns in any given simulation run The traffic model is the α-stable self- similar traffic model

17 Performance

18 Wavelength Plan A trade-off lies between number of the AWG channels and maximum modulation bandwidth

19 Conclusions SUCCESS-DWA can viewed as a scalable network taking advantage of both TDM and WDM The scheduling algorithm in the OLT is responsible for managing the traffic flow for fair access of end users

20 Reference Yu-Li Hsueh, Matthew S. Rogge, Wei-Tao Shaw, and Leonid G. Kazovsky, “SUCCESS-DWA: A Highly Scalable and Cost-Effective Optical Access Network”, IEEE Optical Communication August 2004 Glen Kramer and Gerry Pesavento, “Ethernet Passive Optical Access Network (EPON): Building a Next-Generation Optical Access Network”, IEEE Communications Magazine February