Post on 14-Aug-2020
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25G/50G/100G EPON wavelength plan C
Ed Harstead, member Fixed Networks CTO Dora van Veen, Vincent Houtsma, Bell Labs
Supporters:
John Johnson, Broadcom
Sept. 2016
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Only 25G in O-band: Plan C
kramer_3ca_5_0716.pdf
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25G EPON TRx λ0
WM
Simple diplexer
ODN
S/C/L band
O band 25G ONU
50G/100G ONU
25G OLT TRx λ2
25G OLT TRx λ3
25G OLT TRx λ4
25G OLT TRx λ1
Plan C: high level optical architecture. Focus on 1+4
Step 1: what wavelengths in the S/C/L band for λ1, λ2, λ3, λ4? Step 2: what wavelengths in the O-band for λ0?
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λ1 - λ4 in the S/C/L band: dispersion tolerance
0
50
100
150
200
250
300
1460 1510 1560 1610
Dis
pe
rsio
n (
ps/
nm
)
G.652 spectrum (nm)
Fiber dispersion and dispersion tolerance25 Gb/s, 10 km, 1 dB penalty
w/o dispersion compensation
Fiber dispersion, max abs val
duobinary tolerance, EML
NRZ tolerance, EML
Must design for worst case: NRZ detection
No dispersion compensation required for NRZ detection up to 10 km for wavelengths up to ~1560 nm
• 25G dispersion tolerance values based on simulations.
• Experimental data is welcome.
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Cost-optimized 100G EPON will require an optical pre-amp in the OLT to avoid optical post-amps in the ONU
• EDFAs have lower noise figure than SOAs.
• An EDFA preamp *might* be required to avoid post-amps in 100G ONUs, for PR30
– There are EDFAs that support burst mode
• The need for EDFA might be even stronger for PR40
• EDFA is not an option if 100G wavelengths are in the O-band (Plans A, B, D, E)
100G OLT
λ1 Rx
λ2 Rx
λ3 Rx
λ4 Rx
λ1 Tx
λ2 Tx
λ3 Tx
λ4 Tx
λ d
em
ux
m
ux
Diplexer
-24 dBm
-26.5 dBm
R
OA
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Choosing wavelengths for λ1 - λ4
No dispersion compensation required for
≤10 km
EDFA
1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1460 1470 1480 1490 1500
S-band C-band L-band
NG-PON2 US ITU-T
RF
1524-1560 nm Put US λs here
Sweet spot
10G EPON DS
short end of 10G EPON ONU filter guard band
No co-existence requirements
GPON/ GE-EPON DS
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Wavelength plan for λ1 - λ4. Assume 800 GHz CS
Sweet spot
Pure 100G EPON deployments can take advantage of lower fiber loss at these wavelengths
1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1460 1470 1480 1490 1500
Can maximize DS/US distance for lowest cost filtering
All 800 GHz CS, conforming to industry norm Should be no wavelength drift issue
upstream downstream
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Choosing wavelengths for λ0
1310 1320 1330 1340 1350 1360 nm 1260 1270 1280 1290 1300
Plan C2 down up
Plan C4 down up
up Plan C1 down
TDM co-existence with 10G EPON
WDM co-existence with 10G EPON
Plan C5 down up
Plan C allows for increased flexibility to optimize 25G EPON
– Cost-optimization
– TDM or WDM co-existence with 10G EPON
– Co-existence with gen 1 PONs
The only option for Plan B
Low downstream DML TDP
uncooled DML in ONU
up Plan C3 down EPON US (DFB); GPON
25G co-existence with GE EPON (DFB) and GPON*
OLT DML still an option?
*may support CTC objective: “Promote IEEE and ITU-T coordination” including “Shared Unified wavelength plan” zhang_3ca_1b_0716.pdf
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Dispersion compensation
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If >10 km PONs must be supported, DCF can be deployed in 1+4 (not in 1+3 if DS/US λ0 is in the O-band)
Should be able to support any differential distance.
Characteristics
– Optical loss: e.g. spec: 1.2 dB (10 km)
– Size: e.g. module 9.2”x9.6”x0.75”
– Cost: low, relative to the cost of the 100G OLT transceiver
Dispersion compensation fiber (DCF) for PONs > 10 km
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DCF deployment
50G/100G TxR 50G/100G
ONU
50G/100G TxR 50G/100G
ONU
50G/100G TxR 50G/100G
ONU DCF
OLT
0 km 10 km
PONs ≤10 km don’t require DCFs
• A DCF is installed at the OLT only for PONs >10 km
• The cost and space impact of DCFs is proportional to the % of PONs of >10 km reach. For most (all?) operators this will be small.
• Or, just create a 10 km spec and make the issue go away (e.g. miguelez_3ca_1a_0516.pdf)
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Power budget
14 Public
Optical assumptions
• 100G mux and demux nominally add ~2.5 dB insertion loss each.
• Cost-optimized 100G EPON puts all optical amplification in the OLT
• Downstream TDP = 1.5 dB, upstream TDP = 3 dB (same as 10G EPON, but to be confirmed)
• PR30 loss budget
• There will be 1 dB FEC coding improvement in downstream relative to 10G EPON (to be confirmed)
• 1 dB improvement in PR30 APD receiver performance vs. 10G EPON + 5 dB penalty for 25G (per NeoPhotonics yield analysis, in harstead_3ca_1a_0516.pdf.)
• Launch power values from harstead_3ca_2a_0716.pdf
AVPmin (dBm) ER (dB)
EML 5 8
cooled DML 8 6
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Downstream optical levels (per harstead_3ca_1_0916).
25G λ1 Tx ODN 25G λ1 Rx
25G ONU
100G OLT
S R
λ1 Rx
λ2 Rx
λ3 Rx
λ4 Rx
λ1 Tx
λ2 Tx
λ3 Tx
λ4 Tx
λ d
em
ux
m
ux
Diplexer
λ1 Rx
λ2 Rx
λ3 Rx
λ4 Rx
λ1 Tx
λ2 Tx
λ3 Tx
λ4 Tx
λ d
em
ux
m
ux
Diplexer ODN
25G OLT
100G ONU
-24.5 dBm +5 dBm
-24.5 dBm
-22 dBm +7.5 dBm
Assume EMLs
S R SOA Common OA post amp shown. Per channel OAs can also be considered.
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Upstream optical levels (per harstead_3ca_1_0916).
25G λ1 Rx ODN 25G λ1 Tx
25G ONU
100G OLT
R S
λ1 Rx
λ2 Rx
λ3 Rx
λ4 Rx
λ1 Tx
λ2 Tx
λ3 Tx
λ4 Tx
λ d
em
ux
m
ux
Diplexer
λ1 Rx
λ2 Rx
λ3 Rx
λ4 Rx
λ1 Tx
λ2 Tx
λ3 Tx
λ4 Tx
λ d
em
ux
m
ux
Diplexer ODN
25G OLT
100G ONU
-24 dBm
Assume DMLs
+8 dBm
-24 dBm +8 dBm
+5.5 dBm -26.5 dBm
R S
OA
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25 Gb/s dispersion tolerance (simulated)
Noise contributions, laser linewidth
and non-linearities were not taken into
account in the simulation.
Duobinary:
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10G PON ONU blocking filter
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If GE-EPON and GPON co-existence were required for 100G EPON
1450(I) 1441(I)
(I) = Informative
1415/1400(I) 1530 1539 1580-1625
22 (I)
7 (I)
ONU tolerance to interferers would constrain NG-EPON downstream wavelengths to ≥ 1539 nm.