Terabit Transmission & Software Configurable

OpticsDr. Kevin Smith, Transport Futures and Innovation

© British Telecommunications plc

Talk outline

• Innovations in high-capacity superchannel infrastructures

– New real-time 64GBaud technology

– Emerging software configurable flexible-rate optics

– Flexible grid & Superchannels

– Terabit Superchannel Protection

• Real-world technology trials and deployments

– Closed loop network running between the BT Tower and Adastral Park

– Live commercial flexible grid optical core link between London and Dublin

• Summary

Key Innovations: Degrees of freedom for scaling to

Terabit capacities

Bit

s p

er

Sym

bo

l

Symbol rate

Superchannel

16-QAM

(4bits/symbol)

QPSK

(2bits/Symbol)

25G 50G

2

4 Note: Dual polarisation

Modulation

Format

Bits per

symbol

(single/dual

polarisation)

Net

Baud-

rate

(Gbit/s)

Speed /

subcarrier

(Gbit/s)

Typical

Reach

(km)

Typical

OSNR

requirement

(dB)

QPSK 2/4 25 100* 2000 12

QPSK 2/4 50 200* 1000 16

16-QAM 4/8 25 200* 600 20

64-QAM 6/12 33 400* 150 26

4 x 100G

(QPSK)

2 x 200G

(16-QAM)

1 x 400G

(64-QAM)

150 GHz 75 GHz 50 GHz

The Next Generation: Gridless & optical superchannels

• Current WDM has rigid 50GHz grid structure

– Restricts evolution to Tbit/s speeds & spectral efficiency

• Future gridless infrastructure permits

– Bandwidth growth, 400G and beyond

– Improved fibre utilisation (spectral efficiency)

1.4T Superchannel comprising 7 x 200G (16-QAM) subchannels

8 Tbits/Link 16 Tbits/Link 25 Tbit/s/Link

Industry leading 64GBaud flexible rate optical

transponder technology

• Single slot 400G cards

– 2 optical line outputs

– 64Gbaud capable

– Long reach 200G capability

• Flexible modulation formats– 100G / QPSK

– 200G / 16-QAM

– 200G / QPSK (long reach 200G)

• One card – multiple applications

– Fast bandwidth uplift / upgrade

– Optical protection

– Simplified sparing and inventory

200G DP-QPSK

200G DP-16QAM

100G DP-QPSK

U2000 NMSOSN 9800

Optical Superchannels to 3 Terabit/s

• During the summer of 2014, we successfully

demonstrated error-free transport of up to

3Terabit/s over a fully managed field installed

Flexgrid link

• 3T (15 x 200G 16-QAM sub-carrier) superchannel.

• Real time, production grade hardware & software,

359km field installed fibre and WDM system.

• 3T superchannel co-propagates with conventional

50GHz 100G channels

• 33.5GHz subcarrier spacing giving a spectral

efficiency of 5.97bits/s/Hz, more than 49%

improvement over conventional 50GHz grid

• Configured and managed from BT’s live

Transmission Network Operations Centre (TNOC) in

Cambridge

Norwich

Adastral

park

Newmarket

Cambridge

Colchester

Basildon

Bishops Stortford

BT Tower

Wood green

77km83km

68km

35.805 km

64km

58.1km

62km

57.08km

24km

50.7km

13.8km

14.74km

Ipswich

BT Adastral

Park

BT Tower

Cambridge

TNOC

3T

Superchannel

(15 x 200G 16-QAM)

550 GHz

100G 100G100G

100G

3T

http://www.btplc.com/news/Articles/ShowArticle.cfm?ArticleID=476A9AC1-58A4-44EE-A067-871356A12950

400G Deployment in BT’s Live Network

Newry

Dundalk

Error free

10 & 100GE

over 400G

400G

10G, 40G, 100G & 400G

on Live Link

400G

2 x 200G

(16-QAM)

BELFASTTELEHOUSE

RIVERHOUSEDUBLIN

http://www.btireland.com/pr_2015_02_04_400gbps.shtml

Pushing the limits on capacity & spectral efficiency:

Demonstration of a 5.6Tb/s superchannel

• Error free performance for all the 28×200G DP–QPSK sub-channels with pre-FEC BER <5×10-5

• A small optical penalty (<1dB) for channel separations down to 60GHz compared to 75GHz spacing

• Error free performance achieved for channel spacing as narrow as 51GHz, an improvement of 47% in spectral efficiency

Demonstration of fast optical superchannel

capacity turn-up up to 2Tb per minute

• Modulation format switching time ~35s: (a) 100G QPSK to 200G QPSK; (b) 100G QPSK to 200G 16QAM

• Superchannel capacity switching time <75s from 2.6Tb/s (26×100G) to 5.2Tb/s (26×200G QPSK or 26×200G

16QAM) including 100GE client mapping over all sub-channels fast capacity uplift (network upgrade) of ~2Tb/min

Live 727km flexible grid optical link between

London and Dublin

• The trial was conducted in a live 727km flexible grid G.652 fibre link between London and Dublin with 10 spans including

an unrepeatered submarine cable of 133km• EDFA amplification except for the submarine link where hybrid Raman/EDFA is used

• Flexible grid ROADM nodes located in London, Slough, Bangor and Dublin for traffic ADD and DROP

• 64GBaud flexible rate transponders housed in Huawei 9800 chassis in London and Dublin

2Tb/s optical superchannel and flexible modulation

format signals operating alongside live traffic

• A spectral window of 1.4THz provisioned for the flexible rate 64GBaud optical channels

• 2Tb/s (10×200G QPSK) superchannel operating error free alongside live 40G/100G wavelengths

• A 100G QPSK and 200G 16QAM optical channel also achieving error free performance

• Long term error-free performance for all optical channels

• 200G DP-QPSK shows significantly larger margin and long reach capability

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0 2 4 6 8 10 12 14 16 18

Pre

-FE

C B

ER

Time (hour)

1 × 200G DP - 16QAM channel

1 × 100G DP - QPSK channel

10 × 200G DP - QPSK sub-channels

GTB Award: Fixed Infrastructure Innovation

From 5.6 Terabit/s Innovation to 2Tb/s Live International Trial

Operator: BT

Vendor: Huawei Technologies

http://www.btplc.com/news/#/pressreleases/bt-core-network-trials-break-world-speed-records-1418554

Its not all about speed …

25 Petabits !!

Terabit optical superchannel protection

4 x 100G

(QPSK)

2 x 200G

(16-QAM)BT Adastral

Park BT Tower

400G MAIN

400G

PROTECT

0.8T (Unprotected)

First field trial demonstration of superchannel

protection (400G) & in-service OTDR

400G service recoveryFibre fault location using

in-built OTDR

Summary• Our live trials were conducted over a 727km commercial flexible grid optical core link between

London and Dublin, based on Huawei’s OSN 9800/8800 and iManager U2000 platforms,

carrying live 40/100G customer traffic. The link includes a 133km long unrepeatered submarine

cable link from Dublin to Holyhead.

• A 2Tbps superchannel exploiting commercial flexible grid hardware and real-time flexible rate

64GBaud transponders operating with live 40/100G customer traffic.

• Successful demonstration of real-time 200G 64GBaud transponders allowing all-optical, long

reach (unregenerated) transmission with low latency.

• By exploiting flexible rate transponders, we successfully demonstrated fast capacity turn up

(or network upgrade) equivalent to ~2Tbps in one minute.

• Successful demonstration of a real-time 5.6Tbps superchannel, comprising 28 x 200Gb/s

(64GBaud/QPSK) sub-channels, over a 359km closed loop link running between the BT Tower

and Adastral Park and achieving highest capacity and spectral efficiency.

• Successful field trial demonstrations of optical superchannel protection (400G) and in-service

OTDR fibre fault location.

Acknowledgements

BT: Y. R. Zhou, S. West, M. Johnston, J. Weatherhead, P. Weir, J. Hammond, A. Lord, A. Sugrue,

G. O’Hara, C. Harpur, S. Duff, N. Sheeran, E. Harrington, D. Nolan, D. Gosai, and P. McSorley.

Huawei: J. Chen, W. Pan, C. Cao, R. Yang, N. Zhou, S. Wu J. McGrath, D. Tanasoiu, Z. Xiao, J.

Dwyer, A McConnell, N. Abraham and A. Pigott.