H. Le Minh, Z. Ghassemlooy and Wai Pang Ng Optical Communications Research Group

Simulation of All-optical Packet Routing employing PPM-based Header Processing in Photonic Packet

Switched Core Network

H. Le Minh, Z. Ghassemlooy and Wai Pang Ng

Optical Communications Research GroupNorthumbria University, UK

http://soe.unn.ac.uk/ocr/

First International Conference on Communications and Electronics

HUT - ICCE 2006, 10th-11th Oct. 2006 Hanoi, Vietnam

HUT - ICCE 2006HUT - ICCE 2006

Contents

Introduction

PPM-Header Processing Overview– Operation principle– Clock extraction– PPM address conversion– PPM header correlation– All-optical flip-flop– Wavelength conversion

Simulation Results

Summary


Contents

Introduction

PPM-Header Processing Overview– Operation Principle– Clock Extraction– PPM Address Conversion– PPM Header Correlation– All-optical Flip-Flop– Wavelength Conversion

Simulation results

Summary


Introduction – All-optical network

Network transparency All-optical core router Processing, switching and routing in optical domain high throughput Packet format is preserved

#15

#11

1000

1111

1001

0111 110

1010

1011

#961

…

…

…

…

…

Edge node Core router High-speed optical data packet

Low-speed electrical data packet

Core network

#7 #12

#8

#10

1


Contents

Introduction


Simulation results

Summary


Routing Table

? OP 1

OP 2

OP 3

4-bit

1001B = 9D

Ref: [1] Z. Ghassemlooy et al., NOC 2005, UK, pp. 209-216

[2] Z. Ghassemlooy et al., ICTON 2005, Spain, Vol. 2, pp. 50-53 2

i

Convert to pulse-position routing table


Router Operation

OP 1

OP 2

OP 3

4-bit

1M router

(up to M input packets at M wavelengths)

3

Principle Implementation

WDM

MUX

WDM

MUX

1 2

Input port

Output 1

Output 2

MW- PPRT

WDM DEMUX

… …

WDM

MUX

WDM

MUX

c1

c2

cM

c1 c2

cM …

E1 E2 E3 EM

…

E2 E3 E4 E1

…

EM E1 E2 EM-1

…

E1 E2 E3 EM

CW

…

M 321

… M 321

… M 321

… M 321

PPM-HP 1 @1 …

… PPM-HP 2 @2 …

…

… PPM-HP M @M …

M

2 3

1

M 1

M-1 Output M

PK1@1

PK2@2

PKM@M

...

...

PK1@2

PK3@3

PKM@1

M

PK3@3


Router - PPM-HP

Data H Clk

Data

H Clk

Data H Ck

Clock Extraction

Clk 2

M

1

PPM-ACM

1-N SP Converter

WC-1

WC-M

WC-2

AOFF 1

Address matches with entry 2

Input

Outputs

M

2

1 @2

… …

PPM-HEM

xPPM(t)

BPF 1

BPF 1

&

…

BPF 1

&

&

Data H Ck

Data packet, @1 Data H Clk

x(t)

ci E2 EM

…

AOFF 2

AOFF M

… CW

cSP

E1

PPM-HP module

4


Contents

Introduction


Simulation results

Summary


Payload Header Clk

1 1 0 1 1 0 1 0 1 1 1 1 1 1 0 1 1

Router - PPM-HP - Clock Extraction

Clock extraction requirements:

• Asynchronous and ultrafast response

• High on/off contrast ratio of extracted clock

Clock Extraction

Clock, header and payload:- have the same intensity, polarization and wavelength

5

Clk



22

22

SOA1

SOA2

1222

CP1

CP2

SMZ-1 SMZ-2

Clk

22 12 22

22

22

22in

SW SW

in

12 12

SOA1

SOA2

GCP

Optical delayAttenuatorPolarization Beam Splitter (PBS)

Polarization Controller (PC)AmplifierOptical fiber span

6



22

22

SOA1

SOA2

1222

SMZ-1 SMZ-222 12 22

22

22

22in

SW SW

in

12 12

SOA1

SOA2

GCP



6



22

22

SOA1

SOA2

1222

SMZ-1 SMZ-2

Clk

22 12 22

22

22

22in

SW SW

in

12 12

SOA1

SOA2

GCP



6



(a)

(b)

(c)

(a) Input packets

(b) Extracted clock pulse by single SMZ. The residual signal intensities are high, but eventually fading due to SOA gain is saturated with the stream of high-powered control pulses

(c) Extracted clock pulse by two-inline SMZs. The residual signals are suppressed improving the on/off contrast ratio

Ref: Z. Ghassemlooy et al., ICTON 2006, UK, Vol. 4, pp. 64-67 7


Contents

Introduction


Simulation results

Summary


Router - PPM-HP - Address Conversion

(a) (b)

Switch (0)

Switch (1)

Switch (2)

Switch (3)

a3

a2

a1

a0

x(t)

SMZ3

SMZ2

SMZ1

SMZ0

1-N SP Converter

))

PPM-ACM

cSP

a1 a2 a3 a0

xPPM(t) 20TS

s 1

22TS 1

23TS 21TS 1

(a)(b)

8


Contents

Introduction


Simulation results

Summary


Router - PPM-HP - Header Correlation

SMZ-based AND gate: only one bit-wise operation! SOA gain recovery is no longer an issue, since it is saturated only once for

header recognition

Matched

Ref: R. P. Schreieck et al., IEEE Quantum Elec., Vol. 38, pp. 1053-1061, 2002

2N×M switch matrix …

…

(Optionally) Could be changed to set new

values of entries

c

E1 E2

EM …

12N

xPPM(t)

9

E2(t)


Contents

Introduction


Simulation results

Summary


Router - PPM-HP - All-optical Flip-Flop

- Operate at < nanoseconds responses

- Multiple SET/RESET pulses for compensating the actual loop delay (~ hundreds

of picoseconds) and for speeding up the transient ON/OFF states of Q output

10

CW

:(1 –)

Q

FBL

TFBL

SET

RESET

SOA1

SOA2

Optical delay

Attenuator

Polarization Beam Splitter (PBS)

Polarization Controller (PC)

TSW

PCW

St

Rt

PFBL

TFBL AOFF


Router - PPM-HP - All-optical Flip-Flop

SET (blue) / RESET (red)

SOA1 gain (blue) / SOA2 gain (red)

Q output

ON/OFF Contrast Ratio

11


Contents

Introduction


Simulation results

Summary


Router - PPM-HP - Wavelength Conversion

SOA1

SOA2

CW @ 2

Data packet@ 1

22 22

Data packet@ 2

Ref: Y. Ueno et al., ECOC 2002

12


Contents

Introduction


Simulation results

Summary


Simulation – 13 Router

13

OP 1

OP 2

OP 3

4-bit


Simulation – Parameters

14


Simulation – Input / Clock Extraction

1

2

3

Clk 1

Clk 2 Clk 3

Input packets (3 wavelengths) Input spectrum / Extracted clock pulses

14


Simulation – Router Outputs

PPM-HP1 – Output 1



Router output 1

1 2 3

Spectrum at router output 1

15


Simulation – Router Outputs




Router output 3




Router output 2

16


Simulation – Multiple-hop OSNR

OS

HP

…

# Source

Source Edge-node

Target Edge-node

OS

HP

0,

0

ase

in

P

PG

attn.

attn.

# Target

OSNR0 OSNR1 OSNR2 OSNRH

Optical fiber

Optical pre-amplifier

attn. Attenuator

inP

0,aseP

OS

HP

attn. 0G 01 L 1G

1,aseP 2G

2,aseP 11 L

HL1 11 HL

HG HaseP ,

0,0

00

1 ase

in

PL

PLG

1,0,01

010

asease

in

PPLG

PLGG

1,10,101

1010

1 asease

in

PLPLLG

PLLGG

2,1,120,1021

10210

aseasease

in

PPLGPLLGG

PLLGGG

…

1- Multiple-hop OSNR due to accumulated ASE

2- Predicted & simulated OSNRs

0 1 2 3 4 510

15

20

25

30

35

40

45

Number of hops

OS

NR

(d

B)

Theoretical, OSNR0 = 28dB



Simulation, OSNR0 = 28dB



Ref:

Z. Ghassemlooy et al., IEEE 49th GLOBECOM 2006, USA, (accepted)

17


Contents

Introduction


Simulation results

Summary


Summary

PPM-HP– Provides ultrafast header processing– Reduces the number of routing table entries– Avoids the SOA recovery time during header correlation– Operates in a large BW as employing SOA– Supports multiple transmitting modes (uni/multi/broadcasting)– Offers add/drop edge node scalability

18

Further investigation– ASE noise sources– Timing jitter and pulse dispersion effects on PPM-HP– Effective wavelength conversion– IP-based optical transparent network


Thank you

Documents

H. Le Minh, Z. Ghassemlooy and Wai Pang Ng Optical Communications Research Group