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100G EPON Coexistence

discussion

Dekun Liu

July, 2016

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Background

What method of coexistence is used for 10GEPON is an important factor

for the decision of wavelength plan.

3 channels of 100G EPON will certainly coexist with 10G EPON by WDM.

The only decision is how 25G coexists with 10G.

Considering both symmetric and asymmetric, there are at least 3 possible

coexistence options:

Option 1: 25/25, 25/10, & 10/10 use a same upstream wavelength, TDM

coexistence

Option 2: 25/25 & 25/10 use a same upstream wavelength, WDM coexistence

with 10/10

Option 3: 25/10 & 10/10 use a same upstream wavelength, TDM coexistence,

25/25 uses another upstream wavelength, WDM with 10/10G

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Option 1: TDM coexistent

25G DS

10G/25G

Dual Rx

25/25G US

25/10G US

1270+/-10nm

10G EML Tx

25G b/s Tx

25/10 G

Dual rate Rx

25G OLT 100G OLT

25/10G

Dual Rx1

25G Rx2

25G Rx3

25G Rx4

25G Tx1

25G Tx2

25G Tx3

25G Tx4

10G Tx1

25/25, 25/10 & 10/10G all coexist by TDM.

Main concern:

Low upstream bandwidth efficiency, DBA is complicated.

10G optics are re-done in 25G and 100G, this make the 25G and 100G OLT optics

quite complex

λ

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Option 2: WDM coexistent

25G DS 25/25G US

25/10G US

1270+/-10nm

100G PON (including 25G) coexists with 10G PON by WDM

100G PON and 10G PON are two independent systems, upgrade simplicity

Main concern:

25/10G needs a new type 10G upstream transmitter, can’t re-use the existing

1270nm transmitter in 10G PON.

10G US Splitter 100G

EPON

10G EPON

OLT

10 G

25/10G

100 G

25/25G

100G ONU

10G ONU

λ

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Option 3: TDM & WDM hybrid coexistent

100G and 25G symmetric system coexists with 10G by WDM

25/10G coexists with 10G PON by TDM

25/25 and 25/10G coexists by TDM? Or WDM?

25G DS 25/25G US 25/10G US

λ

25/25G-EPON

1270+/-10nm

25/10G-EPON DS is shared!

1270+/-10nm

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Option 3: 2 type ONUs coexistent

25/25G & 10/10G WDM

25 G TRX

10G TRx 10/10 G

25/25G

1270nm

1290nm

25/10G & 10/10G TDM

25 G TX

10G Rx 10/10 G

25/10G

1270nm

1270nm

10 G TX

25/25G & 25/10G WDM

25 G TX

10G Rx 25/25 G

25/10G

1290nm

1270nm

25 G RX

25/25G & 25/10G TDM

25 G TX

25/10G

Dual Rx 25/25 G

25/10G

1290nm

1270nm

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Option 3: 3 type ONUs coexistent

25/25G, 25/10G & 10/10G WDM

25 G TX

10G Rx

25/25 G

25/10G

25 G RX

10/10 G

10 G TX

25 G TX

25/25 G

25/10G

10/10 G

10 G TX

25/25G, 25/10G & 10/10G TDM

25/10G

Dual Rx

Quadr-plexer OLT module

Triplexer OLT dual rate module

OLT architecture depends on coexistence scenario

Complex optics in OLT are required for 3 type ONU coexistence, as DBA can’t go across

OLT boards.

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Discussion

If we want to re-use existing 1270nm 10G optics for 25/10G, then TDM and complex

100G EPON OLT optics seem to be indispensable.

If we want to uncouple “100G EPON” & “10G EPON”, WDM coexistence, option 2 is the

best choice, then we need to re-consider the following motion.

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Discussion

From the upgrade simplicity and coexistent flexibility considerations, WDM coexistence

between 10G EPON and 100G EPON is a better choice:

Upstream bandwidth efficiency is higher

WDM coexistence can support more co-existence scenarios, as 100G EPON is

uncoupled from 10G EPON.

100G EPON OLT optics will be much simpler in WDM coexistence.

The cost of using another wavelength 10G transmitter other than 1270nm is not

substantial if it’s close in spectrum (such as in 1290nm or ~ 1300nm)

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Straw poll:

I prefer 25G symmetric EPON coexist with 25G asymmetric

EPON by

1. TDM ?

2. WDM ?

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Straw poll:

I prefer:

1. 25G symmetric/asymmetric EPON coexist with 10G EPON by TDM

?

2. 25G symmetric/asymmetric EPON coexist with 10G EPON by

WDM ?

3. 25G symmetric EPON coexists with 10G EPON by WDM, 25G

asymmetric EPON coexists with 10G EPON by TDM ?

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