Chang-Hee Lee WDM-PON overview LG-Nortel ECOC · PDF file LONG Reach WDM-PON >Passive long...

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Transcript of Chang-Hee Lee WDM-PON overview LG-Nortel ECOC · PDF file LONG Reach WDM-PON >Passive long...

  • Always Surpassing Customers ExpectationsLG-Nortel Proprietary Information

    WDM-PON Overview

    2009.9.22

    Chang-Hee Lee

    LG-Nortel and KAIST

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    Content

    2

    > Introduction > Colorless optical sources

    • Broadband optical sources • Injection seeded reflective modulators • Tunable lasers

    > Architectures • Protection • Broadcasting and Video overlay • OTDR • Upgrade to 10G • Long reach PONs

    > WDM-PON global status > Summary

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    Introduction: why p-t-p network?

    > Trends • Bandwidth growth

    • 10 times every 5 years (Nielson’s law, Optical Moore’s law) • Video centric services

    • High, bandwidth, high QoS, long connection time • Picture and video clip exchange

    • Convergence over fiber based optical networks • Voice, data, video, and wireless (2G , 3G, LTE) • Residential and business

    > Observations • Long lifetime of outside plant

    • Fiber and passive devices guarantee > 25 years lifetime. • TDM-PON

    • Ever changing technology: BPON GPON 10 G PON 40 G PON • Limited scalability due to high speed transmission over high loss link

    3

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    WDM PON Values

    > Future proof solution • Future proof Lifetime Outside Plant operation (>25years) • Graceful Upgrade Path to Future High Bandwidth Applications

    >WDM‐PON scales dedicated BW to 1 G, 10 G and beyond > Improved Customer Experience

    • Secure symmetric p‐t‐p connection, No bandwidth sharing • Bit rate and protocol transparencies • Easy protection and fault localization

    > Low Total Cost of Ownership • Low OPEX cost effectively provided by colorless ONTs • Low upgrade cost for future high bandwidth services • One infrastructure for residential and business services • Achieved inflection point for component industrialization start • Significant improvements in WDM and DSP to improve reaches aiding in  cost reduction

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    Colorless optical sources

    > Colorless ONT (ONU) is essential for WDM-PON, since multiple users are connected to a PON.

    > Methods for colorless operation • Broadband light sources

    • A source that covers spectral range of transmission • Suffers slicing losses

    • Injection seeding • Injection of seed light from a CO to ONT • ONT has an reflective modulator • Requires seed light

    • Tunable lasers • A narrow band light tunable over spectral range of transmission • Needs prior information of wavelength

    5

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    Broadband Light Sources

    Broadband Light Source

    SMF

    RNCO

    - A simple method

    - Slicing loss > 1/N - Limitation in modulation bandwidth for some sources - Beat noises for an incoherent sources

    . Beat noise can be mitigated with a low noise multi-wavelength laser (e.g., QD laser).

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    Injection seeded reflective modulators

    Reflective modulator

    SMF

    BLS

    CO RN

    Seeding sources Limiting factors Reflective modulators

    Incoherent light (ASE)

    Source noise F-P LD, RSOA, EA+SOA No restriction on spectral response

    Coherent light (Bank of DFB LDs)

    Reflection noises RSOA, EA+SOA Restriction on spectral response

    Downstream signal (incoherent or coherent)

    Source noise/reflection noise Downstream penalty

    Same as above

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    Reduction of Reflection Noises

    Signal

    Upstream signal

    PD TIA

    After Receiver

    Reflection noise

    Signal

    PD TIA

    After Receiver

    Upstream signal

    Seed light

    November 10, 20098

    Seed light

    Reflection noise

    > Broaden line-width of seed light • Broadband seed light, phase modulation, …

    > Shift of signal spectrum

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    Tunable laser

    Tunable laser

    SMF

    RNCO

    - No slicing loss - Possibly high modulation bandwidth - Low cost tunable lasers are the ultimate end goal. - Coherent detection can improve link budget and channel counts.

    . Needs coherent tunable laser and DSP

    - Needs prior information for tuning wavelength . End to end control may be complex to mitigate.

    - Cost is very high for access applications.

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    Architecture of WDM-PON

    OLT Switch OLT

    Metro Core

    S/W GUI

    C or

    e R

    ou te

    r

    L2 /L

    3 sw

    itc h

    St re

    am

    Se rv

    er

    ONT TVs

    Video Phone PCs

    Phones

    TVs Video Phone PCs

    Phones

    TVs Video Phone PCs

    PhonesHome

    λ1, λ’1

    λ2, λ’2TRx1 TRx2

    TRxn

    TRx3

    BLS A

    λ3, λ’3

    λn, λ’n

    Wireless Access Point

    MDU

    xDSL

    BLS B

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    OLT RN

    2 x 2N A

    W G

    BLS(U) BLS(D)

    Fault Monitor

    Fault Monitor

    Fault Monitor

    Fault Monitor

    Fault Monitor

    TRxEthernet Switch

    TRxEthernet Switch

    TRx Ethernet Switch

    TRx Ethernet Switch

    ONU 1

    ONU N

    Protection of Fiber Faults

    (a) (b)

    vo lta

    ge (a

    rb itr

    ar y

    un its

    )

    Normal Fiber failure

    Upstream

    8ms

    Time (ms) 20 8040 60 v ol

    ta ge

    (a rb

    itr ar

    y un

    its )

    Normal Fiber failure

    Upstream

    9ms

    Time (ms) 20 80 10040 60

    Normal / DF / FF / Both fault (ONU4) Normal / DF / FF / Both fault (ONU8)

    Normal / DF / FF / Both fault (ONU12)

    Switching Time

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    Broadcast/multicast in WDM-PON

    TRx

    EM

    Multicast/ RF overlay

    OLT

    BLS BLSA W

    G•• •

    TRx

    TRx

    OA splitter

    #1 #2

    #3 • • •

    WDM 3

    1×N

    • • •

    RN ONUs

    12

    A W

    G

    ASE or MW Laser

    TRx

    TRx

    TRx

    *EM (External modulator)

    *OA (Optical amplifier)

    2009-11-10

    * Multiple band transmission by using periodic transmission characteristic of AWG

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    Broadcast signal transmission at 1.25 Gb/s channel

    Isolator

    50:50 Coupler F-P LD 1

    Isolator

    F-P LD 2

    Output

    -80

    -70

    -60

    -50

    -40

    -30

    -20

    -10

    0

    1555 1557 1559 1561 1563 1565 1567 1569 1571 1573 1575 Wavelength (nm)

    Po w

    er (d

    B m

    )

    F-P LD@ temp=28.6도12 3456

    7 8910111213

    14 151617

    1819 2021

    0 0 .5 1 1 .5 -150

    -140

    -130

    -120

    -110

    -100

    -90

    -80

    F re q u e n cy (G H z)

    Po w

    er (d

    B m

    )

    100 GHz filtered ASE 100 GHz filtered MI F-P LDs

    100 GHz filtered ASE

    100 GHz filtered MI F-P LDs

    > F-P LD 1, 2 • Front facet reflectivity of F-P LD : 0.1 ~0.2 % • Laser cavity length : 400 um

    > Passive cavity length : 9 cm

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    Fault localization with tunable OTDR

    ONTCO

    λ1

    RN

    20 km

    5 km

    CWDM

    TRX

    A W

    G A W

    G

    L-band BLS 41

    2 3

    PIN-PD

    F-P LD

    Control Unit

    Pulse generator

    Tunable BPF

    Processing Unit

    Tunable OTDR

    TRX

    TRX

    TRX

    TRX

    TRX

    TRX

    TRX

    0 5 10 15 20 25 30 -90

    -85

    -80

    -75

    -70

    -65

    -60

    -55

    -50

    Distance (km)

    Po w

    er (d

    B m

    )

    OTDR Trace

    Ch. 1 0 5 10 15 20 25 30

    -90

    -85

    -80

    -75

    -70

    -65

    -60

    -55

    -50

    Distance (km)

    Po w

    er (d

    B m

    )

    OTDR Trace

    Ch. 2

    0 5 10 15 20 25 30 -90

    -85

    -80

    -75

    -70

    -65

    -60

    -55

    -50

    Distance (km)

    Po w

    er (d

    B m

    )

    OTDR Trace

    Ch. 3 0 5 10 15 20 25 30

    -90

    -85

    -80

    -75