david piehler david.piehler@neophotonics€¦ · example: g.984.6 (03/2008) figure ii-1 (page 32)...

Notes on EPON extender boxes and EPON PMDs

David [email protected]

Extended EPON Study Group · IEEE 802.3 plenary meeting · Atlanta · 9 November 2011

2Piehler · Notes on EPON extender boxes and EPON PMDs · Extended EPON Study Group · IEEE 802.3 plenary meeting · Atlanta· 9 November 2011

In principle, no limit to split ratio with active ExBox

WDM1

WDM2

WDM31

WDM32

1×32single‐mode

Splitter(1 dB excess

loss)

32×1single‐modefiber to photo‐detectorcoupler

(1 dB loss)

TIA

10GTx

L‐bandEDFA

CDRTO OLT MAC

FROMOLT MAC

…

1×64optical splitter

(0.5 dB excess loss)

TO OLT MAC

FROMOLT MAC

…

1×64optical splitter

PRX 30 OLT XFP1

PRX 30 OLT XFP2

PRX 30 OLT XFP31

PRX 30 OLT XFP32

See for example:Chanclou et al., “Investigation into Optical Technologies for Access Evolution,” OFC-2009, paper OWH1.Oishi et al, “Reconfigurable Multi-Port EPON Repeater,” in Asia Communications and Photonics Conference – 2009, paper TuDD6.D. Piehler, “Implementing High [>2048] Split Ratios in any PON,” OFC-2011 , paper NThF4.

Loss-less (mostly noise-less) optical signal splitting and optical signal combination

Loss-less (mostly noise-less) electrical signal splitting and electrical signal combination


OEO vs. all-optical vs. hybrid ExBox approaches –downstream

● Downstream: cw signals from laser(s) can be regenerated by – Optical amplification and optical splitting

• RINOA = -157 dB/Hz + NF [dB] - Pin [dBm]• L-band EDFAs exist at 1577 nm

– Single wavelength operation simplifies and cost reduces.• Semiconductor optical amplifiers (SOAs) exist at 1490 nm.

– Limited in output power by Psat

– Optical to electrical conversion (2R, 3R), (analog or digital) electronics splitting, electrical to optical transmission.

● Both downstream approaches are fairly straightforward.


OEO vs. all-optical vs. hybrid ExBox approaches –upstream

● Upstream burst signals– Optical to electrical to electrical conversion

• In practice burst-mode receiver should be MAC-aware to reproduce PMD performance defined at OLT.

• If remote ExBox does not have data-rate information or reset information, performance can be compromised

• OEO can be enhanced by loss-less mode-coupling receiver.– Optical amplification

• SOA is OK for burst mode, fiber amplifiers require “adjustments”.• Praseodymium optical amplifiers possible at 1310 nm, SOAs available for all wavelengths.• All optical amplifiers challenged to meet 1260 – 1360 nm wavelength specification.• SOAs can act as a “limiting amplifier” improving upstream dynamic range.

– Design rules are complex, but amenable to simplification– Noise is an issue that limits application of standard PMDs

» For Pin ~ –30 dBm noise starts to dominate.» (See RIN equation on previous slide and “Fujitsu” slide in backup)


Backup


OEO PON link extenders –two basic approaches

PX20 ONU TRx

PX20 OLT TRxOLT line card GE-PON extender box PX20 ONU TRx

PX20 ONU TRxPX20 ONU TRxPX20 OLT TRx

PX20 OLT TRx

PX20 OLT TRx

PX20 OLT TRxOLTMAC

PX20 OLT TRxOLT “line card” GE-PON extender box PX20 ONU TRx

PX20 ONU TRxPX20 ONU TRxPX20 OLT TRx

PX20 OLT TRx

PX20 OLT TRx

10GbE / OC-192CWDM /DWDM

OLTMAC

10GbE / OC-192CWDM /DWDM

PON PMDs everywhere

PON PMDs only on distribution side of extender

(for example) (for example)


OEO can be enhanced by loss-less mode-coupling receiver.

WDM1

WDM2

WDM31

WDM32

1×32single‐mode

splitter

32×1single‐modefiber to photo‐detectorcoupler

TIA

L‐bandEDFA

CDR

TOWARDOLT

… 1270 nm

10 Gb/sDFB

laserdriver

WDM


System design with upstream SOAs –Example: G.984.6 (03/2008) Figure II-1 (page 32)

These charts send the message that trunk budget = f (access budget)

andaccess budget = f -1(trunk budget)

andf is complex

and

network engineering rules are derived from

odd shaped polygonsderived fromupstream and downstream amplifier gain, saturation power, and noise figure, as well as PON receiver sensitivities and overloads, and transmitter launch power ranges.


Simple and meaningful specification and design rule

EPONONTEPON

ONTEPONONTEPON

ONTEPONONTEPON

ONTEPONONTEPON

ONTEPONONT

Optical Distribution Networkminimum link = 14 dBmaximum link = 29 dB0 ≤ dODN ≤ 20 km

dynamic range = 15 dB

ONUport

OLTport

EPONOLT

Optical Trunk Line

maximum link = 22* dB @ 1310 nm

20 km ≤ dOTL ≤ (60 km – dODN)

Engineering rules from the extender’s ODN port are exactly the same PX 30 OLT port

* this depends on the user’s maximum OTL link / distance requirements


Do the math:Optical pre-amplifier vs. APD

PINRxTx OA

λ = 1310 nmER = 10 dBdata rate = R

NF = 7 dBη = 0.85 mW/mABe = 0.65 Rith ~ √ Beith = 12 pA / √Hz @ 1.25G

opticalbandpassfilter

gain = G

∆λ = 20 nm

-40 -35 -30 -25 -20 -15-25

-20

-15

-10

-5

input power at optical amplifier dBm

PIN

Rxse

nsiti

vity

at10-1

2BE

R 3 dB4.5 dB

7 dB

1.5 dB

1.25G 2.5G 10GSensitivity with APD only

(M = 6, k = 0.7) →

Numerical model of optical pre-amplifier sensitivity (@10-12

BER) for various data rates with the listed parameters.

In the asymptotic1 limit, an optical pre-amplifier improves the net receiver sensitivity by3 dB at 1.25 G4.5 dB at 2.5G7 dB at 10G

1Realistic improvement is about 1 dB lower than the asymptotic improvement.

Also shown is the relevant GPON (blue dashed) curve (∆λ = 40 nm)

∆λ = 40 nm


Upstream burst-mode SOAs

Source: “Fujitsu pushes PON splitting”, www.lightreading.com, 13 October 2011.

david piehler david.piehler@neophotonics€¦ · example: g.984.6 (03/2008) figure ii-1 (page 32)...

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