WDM-PON Technologies

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WDM-PON Technologies

• 2007.11
• KT ???????
• ???

2

• Content
• Overview of PON Technologies
• WDM-PON Technologies
• Next Generation PON

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1. PON Technologies
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Optical Access Network Technologies

• Point-to-Point Star ( Home Run)

- Huge number of fibers

• Active Optical Network ( AON) / Active Double
  Star

• Difficult to operate active
• switch as outside facility

• Passive Optical Network ( PON) / Passive Double
  Star

• Most favorable
• Optical multiple access
• technologies

CO
. .
. .
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PON Technologies

• TDMA (Time Division Multiple Access)

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PON Technologies

• TDMA (Time Division Multiple Access)

• 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
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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
30dB EPON
16 nominal PX10 US 23dB

Max not defined PX10 DS 21dB
(
up-to 128) PX20 US 26dB

PX20 DS
26dB
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PON Technologies

• TDMA (Time Division Multiple Access)

- 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
14801500nm Dn
14801500nm
Up 12601360nm
Up 12601360nm
(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
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PON Technologies

• SCMA (Sub-Carrier Multiple Access)

LD
fi
LPF
f1
Data source
Data recovery
Linear receiver
?
fi
fi
LPF
Bandwidth gt 2?(data rate)
fn
fi
LPF
OBI (Optical Beating Interference)
RF power
. . .
RF freq.
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PON Technologies

• OCDMA (Optical Code Division Multiple Access)

C1
C1
Data source
Data recovery
Ci
Ci
Cn
Cn
Opt enc
Opt dec

• Spread spectrum
• Frequency hopping
• OOC( Optical Orthogonal Coding )
• OBI

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PON Technologies

• WDMA (Wavelength Division Multiple Access)

LD
?1
?i
?n
WDM MUX/DEMUX
- Colorless ONU
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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 34dB Protocol
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

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2. WDM - PON

• Advantages

- High bandwidth - Protocol/data rate
transparency - High security

• Disadvantages

- Inefficiency in the bandwidth utilization
- Difficulty in the wavelength tuning gt
colorless ONU - Difficulty in the cascaded
topology
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Key Components

• Athermal WDM MUX/DEMUX

- Thin film filter

• Independent of temperature change
• Expensive for large port number

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Key Components

• Athermal WDM MUX/DEMUX

- Athermal AWG (Mechanical control)
- Athermal AWG (Refractive Index control)
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Key Components

• Color-less transmitter

- Bidirectional optical subassembly
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Key Components

• Comparison of optical transmitters

Wavelength control Modulation scheme Modulation speed Colorless ONT Operation bandwidth Remarks
Solitary source at ONT Wavelength specific laser Wavelength specific laser Needed at ONT Direct 10Gbps No Unlimited
Solitary source at ONT Tunable laser Tunable laser Needed at ONT Direct 2.5Gbps Yes 40nm -Wavelength information
Solitary source at ONT Broadband light ASE from LED No Direct 100Mbps Yes gt50nm High splicing loss Dispersion limit for gt1Gbps
Solitary source at ONT Broadband light ASE from SLD No Direct lt1Gbps Yes gt50nm High splicing loss Dispersion limit for gt1Gbps
Solitary source at ONT Broadband light ASE from EDF No External gt10Gbps Yes 30nm High splicing loss Dispersion limit for gt1Gbps
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
Seed from OLT Array of wavelength specific laser at OLT RSOA Needed at OLT Direct 2.5Gbps Yes gt50nm -Back reflection penalty -Two feeder fiber
Seed from OLT Array of wavelength specific laser at OLT FP-LD Needed at OLT and ONT Direct 1Gbps Yes 50nm -Back reflection penalty -Two feeder fiber
Seed from OLT Broadband light at OLT External modulator No External gt10Gbps Yes 3050nm -High power seed light - Dispersion limit for gt 1Gbps
Seed from OLT Broadband light at OLT RSOA No Direct 1Gbps Yes 3050nm -High power seed light - Dispersion limit for gt 1Gbps
Seed from OLT Broadband light at OLT FP-LD No Direct 2.5Gbps Yes 3050nm -High power seed light - Dispersion limit for gt 1Gbps
Seed from OLT Re-modulation of downstream data Re-modulation of downstream data Needed at OLT Direct/ External 2.5Gbps Yes 50nm -Back reflection penalty -Limited dynamic range
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Colorless ONU Technologies

• Why colorless ?

- Difficulty in wavelength tuning in the
subscriber side - Saving of inventory cost
- Saving in the manufacturing cost

• Colorless ONU technologies

- ASE injected FP-LD - ASE injected R-SOA
- Laser injected R-SOS - Tunable LD
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ASE Injected FP-LD

• Operation principle

W/O ASE injection - Mode partition noise
With ASE injection - Mode locked
Injected ASE(AWG transmission) wavelength profile
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ASE Injected FP-LD

• System Architecture

• 32 ch. / 125Mbps
• 20 km

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Multi-band usage of AWG
?C1, ?L1
? ?Ci, ?Li
?Ci, ?Li
?Cn, ?Ln
- Use different grating orders for different
bands
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ASE Injected FP-LD

• Mutually Injected FP-LD for BLS

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ASE Injected R-SOA
Seed for down stream
R-SOA
R-SOA
ONU
PD
. . . .
PD
. . .
Seed for up stream
OLT
- ASE is used as BLS - Error floor due to ASE-ASE
noise
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Laser Injected R-SOA
- Multi-wavelength laser ( DFB-LD array) is used
as seed light (shared) - Reflection noise
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Features of R-SOA
Current injection
Waveguide
HR
AR
R-SOA
Bulk type Quantum Well type
high( 10dB) high( 28dB) 2dBm Possible High
(similar to FP-LD)
Low ( lt2dB) Low ( 20dB) 3dBm Possible low
PDG Gain Saturation output power
Un-cooled operation (0 60?C)
Yield
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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.

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Features of R-SOA
2.4dB
Injection current 80mA
Injection optical power -20dBm
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Reflection Noise in Laser Injected R-SOA
Reflection Problem in Laser injected R-SOA scheme
,
,
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Reflection Noise in Laser Injected R-SOA
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Laser Injected R-SOA
Reflection Loss (dB)
Launching power (dBm)
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Laser Injected R-SOA (Re-modulation)
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Laser Injected R-SOA (Re-modulation)
Saturation Effect
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Laser Injected R-SOA
Bidirectional Single Fiber Single Wavelength
Schemes - ASK-ASK modulation

• 1.25Gbps
• TDM degrades the performance (?)

OFC 2006 OTuC1
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Laser Injected R-SOA
Bidirectional Single Fiber Single Wavelength
Schemes - SCM modulation

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

OFC 2006 OTuC1
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Tunable LD
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Tunable LD
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Tunable LD
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Hybrid Integrated Optical module for WDM-PON
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Hybrid Integrated Optical module for WDM-PON
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3. Next Generation PON

• Features

- Simple Network - High bandwidth -
WDM
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Future Services

• Immersive Video Communication

Image Acquisition
Reconstruction Rendering
MPEG-4 Encoding/Decoding
4 cameras display
Central Office
Subscriber
Transport Network
Access Network

• Face-to-face Realism
• Resolution, Latency, Jitter, Synchronization
• Motion parallax, Reciprocal Gaze
• Requires multiple cameras, Image Processing, and
  Image Reconstruction

ScientificAmerican.com 2001 April
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Future Services

• Utility Computing

Intelligent Network OS
Dummy
Intelligence
MPC Platform (Web2.0)
New Value

• - User Convenience
• Free from management, virus, upgrade
• Access from anywhere
• - Reduction of TCO
• Sharing of Hardware (CPU/RAM/Hard) and software

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Simple Network
Metro Network 50km SDH, Ethernet,,WDM
Access Network 5km DSL PON
Core Network 200km SDH,WDM, OXC
Access Network 50km NG-PON
Core Network 200km ROADM
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Capex/Opex Savings by the simple Network
Power Consumption
Space
900 racks
826KW
20 racks
50100KW
100W
1 racks
For 15,000 subscribers
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Capex Savings Conventional FTTH v.s. Long
Reach PON
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Technical Direction (FSAN)

• NGA
• PHY layer
• WDM, 10G and/or
• longer reach / higher split
• MAC layer
• Full service
• Matching with new functions
• (eg FEC, wavelength OAM)

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

G-PON GE-PON

• WDM technologies
• Colorless optics
• (tunable lasers filters, )
• Wavelength OAM

Bitrate per wavelength (Gbps)
Video overlay
B-PON
STM-PON
1
2
4
8
16
32
Number of wavelengths
Full Service Access Network
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Evolution Scenario (FSAN)
Co-existence arrows mean to allow gradual
migration in the same ODN.
NGA2 E.g. Higher-rate TDM DWDM Elect.
CDM OFDM,Etc.
Capacity
NGA1 incl. long-reach option
Equipment be common as much as possible
WDM option to enable stacked G/XGPON and/or
PtoP overlay
Co-existence 2)
XG-PON (Up 2.5G, 5G and/or 10G, Down 10G)
G-PON
Co-existence
Splitter for NGA2 (power splitter or something
new)
GE-PON
Power splitter deployed for Giga PON (no
replacement / no addition)
Now 2010 2015
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Stacked PON
G-PON ONU
G-PON OLT
. .
?1,C , ?1,L
NG-PON ONU
. .
?1,C , ?1,L
Power splitter
C/L band
?2,C , ?2,L
WDM2
NG-PON OLT
?1,C , ?1,L
WDM1
?2,C , ?2,L

• Overlay of multiple TDM-PON over the same Optical
  Distribution Network of
• legacy PON
• - Co-exist with the legacy PON

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Evolution Scenario Using WDM-PON

• Current configuration of Broadband Access Network

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Evolution Scenario Using WDM-PON

• Upgrade of Access Network for MDU

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Evolution Scenario Using WDM-PON

• 1st Stage

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Evolution Scenario Using WDM-PON

• 2nd Stage

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Hybrid WDM/TDM-PON

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

OFC 2006 OTuC4
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Hybrid WDM/TDM-PON

• Remotely pumping

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Hybrid WDM/TDM-PON

• Performance analysis

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Hybrid WDM/TDM-PON

• Performance analysis

L1 6dB, L2 14.5dB, LAWG 3.5dB R1, R2 33dB,
R3 38dB, R4 40dB
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Hybrid WDM/TDM-PON

• Experimental set up

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Hybrid WDM/TDM-PON

• Experimental results