Optical Packet Synchronizer

ICE541 Concrete Mathematics

20022037 Kim jinah 20032001 Gang kwang wook

Design of OPSyDesign of OPSy (Optical Packet Synchronizer)(Optical Packet Synchronizer)

Optical Packet Synchronizer

ICE541 Concrete Mathematics

What is OPSy (Optical Packet Synchronizer) ?What is OPSy (Optical Packet Synchronizer) ?

In an asynchronous optical network system, each transmitter node sends out optical packetsasynchronously. The electric control systems for switching these packets at an optical packetswitching node(OPSw) are much simpler when incoming packets are aligned in a series ofcommon time slots provided at the OPSw. This alignment call, which is also called packet synchronization, is a key technology for the development of OPSw, and it achieved using an optical packet synchronizers (OPSy).

IntroductionIntroduction

Optical Packet Synchronizer

ICE541 Concrete Mathematics

coupler2x2 SwitchSignal(1550nm) circulator

High dispersive fiber

WCDFB LD (1540nm) WC

DFB LD (1550nm)

coupler2x2 SwitchSignal(1550nm) circulator

High dispersive fiber

WCDFB LD (1560nm) WC

DFB LD (1550nm)

Ch 1

Ch 2

2R regeneration

2R regeneration

Fiber Delay Loop

Proposed Sync. systemProposed Sync. system

Optical Packet Synchronizer

ICE541 Concrete Mathematics

Sync. System conditionsSync. System conditions - Testing 1 channel with 12 frequency

- - Time slot & packet format ·Time slot : 1024ns · Packet length : 896ns · Guard time : 128ns

- DCF condition · Delay : 1.26ns/km

· Dispersion : -90ps/nm km · Dispersion slope : 0.21ps/nm2km

How’s it proceedHow’s it proceed

- 12 optical packet generate randomly - Aligning Optical packets in ascending order - Calculating proper guard times each packets - Finding 12 optical packets delay times - Finding # of circulating fiber loop - Calculating the efficiency of signal channel on 12 optical packets

Sync. System algorithmSync. System algorithm

Time slot(1024ns)

Packet length(896ns)

Guard time (128ns)

IEEE Photonic Technology Letter. Sep. 2002

Freq 1

Freq 2

Freq 3

Freq 12

… …

∆t1

∆tn

•Misalignment of packets (12 frequency)

Optical Packet Synchronizer

ICE541 Concrete Mathematics

Results of programming Results of programming (using C Language)(using C Language)

12 channel frequency generate randomly

1004 964 934 1005 964 1007 968 988 953 906 973 911

12 channel frequency in ascending order

906 911 934 953 964 964 968 973 988 1004 1005 1007

Calculate 12 channel frequency’s appropriate guard time

118 113 90 71 60 60 56 51 36 20 19 17

Aligning 12 channel frequency’s

1024 2048 3072 4096 5120 6144 7168 8192 9216 10240 11264 12288

Finding 12 channel frequency’s delay times

118 1137 2138 3143 4156 5180 6200 7219 8228 9236 10259 11281

Finding 12 channel frequency’s fiber loop circulating counts

0.00 8.54 16.94 25.36 33.86 42.45 51.00 59.54 68.00 76.45 85.03 93.60

Finding 12 channel frequency’s number of fiber looping

0 8 16 25 33 42 50 59 68 76 85 93

Calculate the efficiency of signal channel on 12 channel frequencys : 99.87

Optical Packet Synchronizer

ICE541 Concrete Mathematics

Results of simulation Results of simulation (using VPI simulation tool and origin )(using VPI simulation tool and origin ) - Delay result of signal after passing DCF: 1km / 100km - Delay result of signal after passing DCF: 1km / 100km

Delay : ~250ns

Optical Packet Synchronizer

ICE541 Concrete Mathematics

-30 -25 -20 -15 -10 -5 0 51E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1SOA current : 200mA, Gaussian filter

Input Power 10 dBm 6 dBm 0 dBm -5 dBm -10 dBm -15 dBm

Bit E

rror

Rat

e

Laser Power (dBm)

Results of simulation Results of simulation (using VPI simulation tool and originPro6.1 )(using VPI simulation tool and originPro6.1 )

-35 -30 -25 -20 -15 -10 -5 0 51E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

1Input power : 5dBm, delay time : 100ps

Bit

Erro

r Rat

e

Laser Power (dBm)

SOA Current 200mA 180mA 150mA 120mA 100mA

BER vs. Input power (“Optimum value:6dBm input power”)

BER vs. SOA current (“Optimum value:200mA”)

Optical Packet Synchronizer

ICE541 Concrete Mathematics

: Problems of Dispersion and Distortion effect - Using some modified sync. System : Using filter and SOA

20km 50km 100km

- Signal Distortion in DCF- Signal Distortion in DCF

Results of simulation Results of simulation (using VPI simulation tool and originPro6.1 )(using VPI simulation tool and originPro6.1 )

- Signal Dispersion in DCF- Signal Dispersion in DCF

20km 50km 100km

Optical Packet Synchronizer

ICE541 Concrete Mathematics

- Modified Sync. System- Modified Sync. System

Results of simulation Results of simulation (using VPI simulation tool and originPro6.1 )(using VPI simulation tool and originPro6.1 )

SOA

Optical Filter

coupler2x2 switchSignal

DCF

- BER measurement (SOA)- BER measurement (SOA)

-30 -25 -20 -15 -10 -5 0 5

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Bit E

rror

Rat

e

Laser Power (dBm)

SOA without Loop SOA within Loop

Input power : 5dBmSOA current : 200mALoop delay time : 100nsWith Bandpass filter

Optical Packet Synchronizer

ICE541 Concrete Mathematics

Input power : 5dBmSOA current : 200mA

-30 -25 -20 -15 -10 -5 0 51E-6

1E-5

1E-4

1E-3

0.01 delay time = 0ns delay time = 10ns delay time = 20ns delay time = 50ns delay time = 100ns delay time = 150ns delay time = 200ns

Bit

Erro

r Rat

e

Laser Power (dBm)

- BER measurement (No filter)- BER measurement (No filter)

Results of simulation Results of simulation (using VPI simulation tool and originPro6.1 )(using VPI simulation tool and originPro6.1 )

-30 -25 -20 -15 -10 -5 0 5

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

Input power : 5dBm, SOA current : 200mA

Without filter FBG filter Gaussian filter Trapezoid filter

Bit

Erro

r Rat

e

Laser Power (dBm)

- BER measurement (with filter)- BER measurement (with filter)

Optical Packet Synchronizer

ICE541 Concrete Mathematics

- BER test (2.5Gb/s modulation)- BER test (2.5Gb/s modulation)

Results of simulation Results of simulation (using VPI simulation tool and originPro6.1 )(using VPI simulation tool and originPro6.1 )

- BER test (10Gb/s modulation)- BER test (10Gb/s modulation)

Optical Packet Synchronizer

ICE541 Concrete Mathematics

11stst - 1.26ns/km delay for the DCF- timeslot of 1024ns- total fiber length = 92~km (very rough calculation)

Very large volume !!Very large volume !!

DiscussionDiscussion

22nd nd

- Optimum power of 5dBm - Optimum SOA current of 200mA - With bandpass filiter (very rough calculation)

BER of 10Gb/s modulation is not so badBER of 10Gb/s modulation is not so badBut, BER of 2.5Gb/s modulation is so badBut, BER of 2.5Gb/s modulation is so bad

Optical Packet Synchronizer

ICE541 Concrete Mathematics

After term project

• We adopted many algorithms such as random and sort to implement OPSy, although this topic is not directly related to Concrete Mathematics.

• Optical Network is coming up topic in Management field. Therefore, what we done is helpful to understand new technology and make more efficient decision.

• We focus on the studying and planning before mid-term presentation. After mid-term presentation, we focus on the real implementation.

• We finished implementing the Optical Packet Synchronizer. But We didn’t check up the efficiency of this algorithm. It will be our further works.