1 wdm-pon technologies 2007.11 kt 미래기술연구소 박수진. 2 future technology laboratory...

1

WDM-PON Technologies

2007.11

KT 미래기술연구소 박수진

2Future Technology Laboratory

Content

1.Overview of PON Technologies

2.WDM-PON Technologies

3.Next Generation PON


1. PON Technologies


Optical Access Network Technologies

Point-to-Point Star ( Home Run)

..

.. CO

Active Optical Network ( AON) / Active Double Star

..

.. CO

Passive Optical Network ( PON) / Passive Double Star

..

.. CO

- Huge number of fibers

- Difficult to operate active switch as outside facility

- Most favorable - Optical multiple access technologies


PON Technologies

TDMA (Time Division Multiple Access)


PON Technologies


- Downstream packet contains id for intended ONU and uses encryption.

- ONU gets synchronized with OLT using the downstream traffic

- Dynamic bandwidth allocation is possible

- OLT ranges the transmission time for each ONU and allocate time slots to

avoid the collision at the splitter .

- Burst-mode upstream traffic

Continuous mode data

Burst mode data

Burst packet data


PON Technologies

Commercial TDM-PON products

- B-PON ( ITU-T Rec. G.983 series)

- G-PON ( ITU-T Rec. G.984 series)

- GE-PON (IEEE 802.3ah)

Power budgets

Type split ratio power budget

BPON 32 max Class A : 20dB Class B : 25dB Class C : 30dB GPON 64 max Class A : 20dB Class B : 25dB Class C : 30dBEPON 16 nominal PX10 US : 23dB Max not defined PX10 DS : 21dB ( up-to 128) PX20 US : 26dB PX20 DS : 26dB


PON Technologies


- Physical layer requirements of G-PON and E-PON standards

FSAN / ITU-T G-PON IEEE E-PON

MAC layer Service Full services (Ethernet, Ethernet data TDM, POTS) Frame GEM frame Ethernet frame PHY layer Distance 10/20km(Logical : 60km) 10/(20)km Branches 64 (Logical : 60km) 16 or over Bit rate Up : 156M, 622M 1.25 Gbps (Up 1.25Gbps and down) Down : 1.25Gbps, 2.5Gbps Coding Scrambled NRZ 8B/10B Opt. loss 15/20/25dB 15/20dB Wavelength Dn : 1480~1500nm Dn : 1480~1500nm Up : 1260~1360nm Up : 1260~1360nm (Video overlay band (Video overlay band available) available) Upstream Guard : 25.6ns Laser turn on/off : burst timing Preamble : 35.2ns 512ns(max) Delimiter: 16.0ns AGC setting and CDR lock : 400ns


PON Technologies

SCMA (Sub-Carrier Multiple Access)

Linear receiver

f1Data sourc

e

LD

fi

fn

fi LPF

fi LPF

fi LPF

OBI (Optical Beating Interference)

Bandwidth > 2*(data rate)

. . .RF

power

RF freq.

Data recovery


PON Technologies

OCDMA (Optical Code Division Multiple Access)

Data sourc

e

Data recovery

C1

- Spread spectrum - Frequency hopping- OOC( Optical Orthogonal Coding )

-OBI

Ci

Cn

C1

Ci

Cn

Opt enc Opt dec

NCC ii jiCC


PON Technologies

WDMA (Wavelength Division Multiple Access)

1

i

n

LD

WDMMUX/DEMUX

- Colorless ONU


PON Technologies

Comparison

Multiple scheme TDMA SCMA CDMA WDMA

Guaranteed BW line rate/N Line rate Line rate Line rate Burst mode upstream No No No Statistical gain Yes No No No MAC Required No need No need No need Timing Control Required NO need No need Depends on scheme QoS Priority Guaranteed Guaranteed Guaranteed management

Splitting loss 1/N 1/N 1/N 3~4dBProtocol No Yes Yes Yes Transparency

Wavelength control No Partial Yes No Yes Remarks Burst mode Linear Rx Linear Rx WDM MUX receiver OBI High speed OBI suppression colorless transmission suppression High speed ONU transmission


2. WDM - PON

- High bandwidth

- Protocol/data rate transparency

- High security

Advantages

Disadvantages

- Inefficiency in the bandwidth utilization

- Difficulty in the wavelength tuning => colorless ONU

- Difficulty in the cascaded topology


Key Components

Athermal WDM MUX/DEMUX

- Thin film filter

- Independent of temperature change- Expensive for large port number


Key Components

Athermal WDM MUX/DEMUX

- Athermal AWG (Mechanical control)

- Athermal AWG (Refractive Index control)


Key Components

Color-less transmitter

- Bidirectional optical subassembly


Key Components

Comparison of optical transmitters Wavelength control

Modulation scheme

Modulation speed

Colorless ONT

Operation bandwidth

Remarks

Solitary source at ONT

Wavelength specific laser Needed at ONT Direct 10Gbps No Unlimited

Tunable laser Needed at ONT Direct ~2.5Gbps Yes 40nm -Wavelength information

Broadband light:

ASE from

LED No Direct ~100Mbps Yes >50nm -High splicing loss-Dispersion limit for >1GbpsSLD No Direct <1Gbps Yes >50nm

EDF No External >10Gbps Yes 30nm

Seed from OLT

Array of wavelength specific laser at OLT

External modulator

Needed at OLT External 2.5Gbps Yes Unlimited -Back reflection penalty

-Two feeder fiber

RSOA Needed at OLT Direct 2.5Gbps Yes >50nm

FP-LD Needed at OLT

and ONT

Direct ~1Gbps Yes 50nm

Broadband light at OLT

External modulator

No External >10Gbps Yes 30~50nm -High power seed light

- Dispersion limit for > 1Gbps RSOA No Direct ~1Gbps Yes

FP-LD No Direct 2.5Gbps Yes

Re-modulation of downstream data

Needed at OLT Direct/

External

~2.5Gbps Yes 50nm -Back reflection penalty

-Limited dynamic range


Colorless ONU Technologies

- Difficulty in wavelength tuning in the subscriber side

- Saving of inventory cost

- Saving in the manufacturing cost

Why colorless ?

Colorless ONU technologies

- ASE injected FP-LD

- ASE injected R-SOA

- Laser injected R-SOS

- Tunable LD


ASE Injected FP-LD

Operation principle

W/O ASE injection

- Mode partition noise

With ASE injection

- Mode locked

Injected ASE(AWG transmission) wavelength profile


ASE Injected FP-LD

System Architecture

-32 ch. / 125Mbps-20 km


Multi-band usage of AWG

Ci, Li Ci, Li

C1, L1

Cn, Ln wavelength

mdnLndn oscis sinsin

- Use different grating orders for different bands


ASE Injected FP-LD

Mutually Injected FP-LD for BLS


ASE Injected R-SOA

R-SOA

PD ...

R-SOA

PD....

Seed for down stream

Seed for upstream

ONU

OLT

- ASE is used as BLS

- Error floor due to ASE-ASE

noise


Laser Injected R-SOA

- Multi-wavelength laser ( DFB-LD array) is used as seed

light (shared)

- Reflection noise


Current injection

HR

AR

Waveguide

R-SOA

Bulk type Quantum Well type

PDG

Gain

Saturation output power

Un-cooled operation(0 ~ 60C)

Yield

Low ( <2dB)

Low (~ 20dB)

~3dBm

Possible

low

high( ~10dB)

high(~ 28dB)

~2dBm

Possible

High (similar to FP-LD)

Features of R-SOA


- Bulk type InGaAsP waveguide - 7 angled waveguide to reduce the reflection - Strain Controlled to reduce the polarization dependency - Spot-size converted to obtain high coupling efficiency - Packaged into TO-CAN / SFF BiDi Transceiver module- ETRI, Opto-On Inc.

Features of R-SOA


1500 1520 1540 1560 1580 1600

-44

-42

-40

-38

-36

-34

-32

-30

-28

Op

tica

l Po

wer

(d

Bm

)

Wavelength (nm)

0 20 40 60 80 100 120 140-40

-30

-20

-10

0

10

20

30

Gai

n (

dB

)Current (mA)

TE Gain TM Gain

Injection current : 80mA Injection optical power : -20dBm

2.4dB

Features of R-SOA


Reflection Problem in Laser injected R-SOA scheme

2

1

221210

2

10

20 ))()(cos(2))()(cos(

kkkk

kp EttEEttEEEi

220

22

20

21

20

20

22

21

)(

2

E

EEEE

i

iiRIN

glE 220 rE 2

1 rglE 2222 , ,

Reflection Noise in Laser Injected R-SOA


Reflection Noise in Laser Injected R-SOA


1.00E-10

1.00E-08

1.00E-06

1.00E-04

-36 -34 -32 -30 -28

Received power (dBm)

BER

-7dBm

-10dBm

2dBm

5dBm


25

27

29

31

33

-4 -2 0 2 4 6

Launching power (dBm)

Re

fle

cti

on

Lo

ss

(d

B)


Laser Injected R-SOA (Re-modulation)

SML

PD


Saturation Effect

Laser Injected R-SOA (Re-modulation)


Bidirectional Single Fiber Single Wavelength Schemes- ASK-ASK modulation

OFC 2006 OTuC1

- 1.25Gbps - TDM degrades the performance (?)



Bidirectional Single Fiber Single Wavelength Schemes- SCM modulation

- No performance degradation- Lessen the Rayleigh backscattering- Low modulation speed

OFC 2006 OTuC1



Tunable LD


Hybrid Integrated Optical module for WDM-PON


3. Next Generation PON

- Simple Network

- High bandwidth

- WDM

Features


Image Acquisition

Reconstruction &Rendering

MPEG-4 Encoding/Decoding

SubscriberCentral Office

Access Network Transport Network

~ 4 cameras + display

- Face-to-face Realism

- Resolution, Latency, Jitter, Synchronization

- Motion parallax, Reciprocal Gaze

- Requires multiple cameras, Image Processing, and Image Reconstruction

ScientificAmerican.com 2001 April

Immersive Video Communication

Future Services


- User Convenience Free from management, virus, upgrade Access from anywhere

- Reduction of TCO Sharing of Hardware (CPU/RAM/Hard) and software

IntelligentPC OS

Dummy

Network

New Value

MPC Platform (Web2.0)

DummyIntelligent Network OS

Intelligence

Utility Computing

Future Services


Simple Network

Access Network~5kmDSLPON

Metro Network~50km

SDH, Ethernet,,WDM

Core Network~200km

SDH,WDM, OXC

Access Network ~50kmNG-PON

Core Network~200kmROADM


* Space * Power Consumption

900 racks

20 racks

1 racks

826KW

50~100KW

100W

* For 15,000 subscribers

Capex/Opex Savings by the simple Network


FSAN PON 1:1

Duct Build

Fibre Enclosures

Fibre Cable

Splitters

SDH Backhaul

ExchangeElectronics

50% Penetration, No Duct Build

FS

AN

PO

N -

ba

ck

ha

ul

Cos

t pe

r C

usto

mer

ONU's

Fibre Enclosures

Fibre Cable

Splitters

Backhaul

ExchangeElectronics

Urban

Rural

Lo

ng

Re

ac

h P

ON

FS

AN

PO

N -

ba

ck

ha

ul

Lo

ng

Re

ac

h P

ON

Capex Savings : Conventional FTTH v.s. Long Reach PON


Bit

rate

per

wav

elen

gth

(G

bp

s)

Number of wavelengths

B-PON

G-PONGE-PON

1 2 4 8 16

0.1

1

10

32

STM-PON

Videooverlay

WDM technologies-Colorless optics (tunable lasers & filters, …)-Wavelength OA&M

NGA-PHY layer

WDM, 10G and/or longer reach / higher split

-MAC layerFull serviceMatching with new functions (eg: FEC, wavelength OA&M)

10G technologies incl. long-reach/high-split technologies-Low-cost optics (direct mod, EDC, FEC…)-Burst-mode receivers

Technical Direction (FSAN*)

* Full Service Access Network


Now ~2010 ~2015

Power splitter deployed for Giga PON(no replacement / no addition)

Splitter for NGA2(power splitter or something new)

G-PON

GE-PON

WDM option to enable stacked G/XGPON

and/or PtoP overlay

Co-existence 2)

“Co-existence” arrows mean to allow gradual migration in the same ODN. NGA2

E.g. Higher-rate TDMDWDM

Elect. CDMOFDM,Etc.

Equipment

be common

as much as

possible

NGA1 incl. long-reach optionC

apac

ity

XG-PON(Up: 2.5G, 5G and/or 10G,

Down: 10G)

Co-existence

Evolution Scenario (FSAN)


Stacked PON

NG-PON OLT

NG-PONONU

Power splitter

G-PON OLT

WDM1

C/L band

G-PON ONU

.

.

.

.

1,C , 1,L

2,C , 2,L WDM2

1,C , 1,L

2,C , 2,L

1,C , 1,L

-Overlay of multiple TDM-PON over the same Optical Distribution Network of

legacy PON

- Co-exist with the legacy PON


Evolution Scenario Using WDM-PON

Current configuration of Broadband Access Network



Upgrade of Access Network for MDU



1st Stage



2nd Stage


Hybrid WDM/TDM-PON

-1.25Gbps re-modulation- 2 feeder fibers required for 1 x8 splitting

OFC 2006 OTuC4


Hybrid WDM/TDM-PON

Remotely pumping


Hybrid WDM/TDM-PON

Performance analysis

22

122

221

2 GGLLLE AWGSig

32

122

1121 RGLLRE AWGR

)( 22

122

2422

21

222

21

22 RGLLRGGLLLE AWGAWGR

2/1

221

222

21

221

2224

22

21

222

213

21

2211 )

)()(2(

1

GGLLL

RGLLRGGLLLRGLLRQ

AWG

AWGAWGAWG

RIN


Hybrid WDM/TDM-PON

L1: 6dB, L2 : 14.5dB, LAWG : 3.5dB

R1, R2: 33dB, R3 : 38dB, R4 : 40dB

Performance analysis


Hybrid WDM/TDM-PON

Experimental set up


Hybrid WDM/TDM-PON

Experimental results

EDF input

Seed

(dBm)

EDF output

Seed

(dBm)

Gain

Seed

(dB)

1544.7nm -19. 20 -4. 43 14. 77

1552.7nm -17. 87 -2. 94 14. 93

1559.9nm -17. 58 -2. 33 15. 25

EDF input

Upstream

(dBm)

EDF out

put

Upstream

(dBm)

Gain

Upstream

(dB)

1544.7nm -29. 13 -14. 19 14. 94

1552.7nm -27. 81 -12. 57 15. 24

1559.9nm -27. 70 -12. 47 15. 23

1 wdm-pon technologies 2007.11 kt 미래기술연구소 박수진. 2 future technology laboratory...

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