upgrade scenario for legacy systems and achievable system cost

For internal use

Multi-mode SDM systems: upgrade scenario for

legacy systems and achievable system cost

25.09.2013

Maxim Kuschnerov1, Vincent Sleiffer²

1: Coriant R&D GmbH, ModeGap

2: TU Eindhoven, ModeGap

© Coriant © Coriant For internal use

New potential technologies for optical communications

M. Kuschnerov 2

4 x 100G QPSK

150GHz

3000km

5 x 200G 16QAM

200GHz

800km

…

200GHz

1569.59 1568.77 1531.12 1530.33 , nm 1569.18 1568.36 1530.72 1531.52

400G

1T

200G

Sym

bo

ls p

er

bit

40G

100G

25GHz

50GHz 50GHz 87.5GHz

2013

Multi-mode (solid / hollow core)

Multi-core

Orbital angular momentum

Ribbon fiber

2020

Coherent superchannels


What is SDM over multi-mode fibers?

• Transmission of independent

channels over orthogonal modes of

a multi-mode fiber

• Capacity is increased by the number

of modes

• Mode-Xtalk can be compensated

using signal processing

M. Kuschnerov 3


Advantages vs. other SDM technologies › Highest possible integration

› Lowest overall system costs (integrated amplifiers and ROADMs)

› Easier handling/splicing

› Lowest nonlinearity (hollow-core)

› Lowest achievable latency (hollow-core)

› Lowest potential loss (hollow-core)

› Higher bandwidth (hollow-core)

Why multi-mode technology?

M. Kuschnerov 4


Technologies developed within the project

• Integrated mode-mux / dmux

› Photonic Integrated Mode Coupler 3D waveguide

• Prototypes presented for 3 modes

• Design is scalable beyond 3 modes

M. Kuschnerov 5



• Multi-mode amplifier

M. Kuschnerov 6

LP01 LP11a LP11b

-30 -20 -10 0 10 20 30-0.002

0.000

0.002

0.004

Core [m]

FRIP

LP01

LP11

Phase plate

DM

(HR=980, HT=1550nm)

DM

Pump LD

(=980nm)

SMF

signal

Pump

(Breadboard dimension=30x45cm)

TMF

TMF

1530 1540 1550 15600

5

10

15

20

25

Gai

n [d

B]

Wavelength [nm]

19.5dBm: LP01, LP11a, LP11b



Pp:



• Solid core multi-mode fiber (3 & 6 modes) Hollow core multi-mode fiber

• All Tx / Rx components @ 2µm

• Thulium doped fiber amplifiers @2µm

• Scalable digital signal processing for SDM

M. Kuschnerov 7


Records set in Modegap

• 57.6Tb/s record capacity over solid-core multi-mode fiber 1

• 57.6Tb/s record capacity over hollow-core photonic bandgap fiber ²

• First higher-order modulation transmission over multi-mode fiber (solid & hollow) 1&2

• First coherent transmission over hollow core fiber ²

• Highest reach (>1,000km) over multi-mode fibers with inline multi-mode amplifiers

1 V.A.J.M. Sleiffer et al., “73.7 Tb/s (96X3x256-Gb/s) mode-division-multiplexed DP-16QAM transmission with inline MM-EDFA”,

ECOC 2012 postdeadline.

² Y. Jung et al., “First Demonstration of a Broadband 37-cell Hollow Core Photonic Bandgap Fiber and Its Application to High

Capacity Mode Division Multiplexing”, OFC 2013 postdeadline

M. Kuschnerov 8


Customer view on Space Division Multiplexing #1

• The customers want to stay with the installed fiber base as long as possible › Installed fiber base is often ~20 years old with no upgrades done in a long time

› 400Gb/s the middle term solution for more spectral efficiency (2016+) target metro

› C+L band afterwards (esp. customers who lease fiber)

› Verizon costs for US network upgrade: $1B

• Sufficient installed capacity › No urgent need of capacity: “we still can provide enough capacity for the near future / till 2020”

› Important to distinguish between operators who own or lease fiber

• There’s a fear of new technology › Many carriers had problems in the field with a new SMF fiber types not even advanced SMF fibers will be

deployed until they are fully tested and understood

› Some carriers claim to never deploy multi-mode fiber under current management

› Every carrier has a long history of new technology failing in the field (basically every component in a

system). Replacing everything at once is not an option

M. Kuschnerov 9



• Look for cheaper alternatives › Fiber bundles with ribbon fiber

› Combine with proven, compatible single mode technology

• Prefer different SDM technology › NTT / Japan is set on multi-core for research, with unclear advantage vs. multi-mode

› Transitional networks prefered that can support fiber ribbons and multi-core fiber

• Consider the correct timeline › AT&T sees SDM needed for 2025

› 400G ramping up in 2016-2018 (400G Ethernet standard not before 4016)

• SDM for political reasons / marketing › Supplier has a few-mode amplifier on the roadmaps without committed timelines

• Too high economic investment › Full eco-system of components needs to be developed (with multiple sources) before a commitment for a

system can be made

M. Kuschnerov 10



• Excitement about the general technology › Customers are very excited about the new technology when they actually see it

› None of the customers in the lab has seen something like this before

› In total, we spent many hours discussing all the technology variants with the customers in a vivid interaction

› Huge excitement for hollow-core technology. Customers didn’t believe it works

• New technology must fulfill certain requirements › Cost / bit must be clearly lower than legacy systems

› Number of channels must stay the same as in current 100G systems

› Gradual upgrade of links should be possible (replace one span by multi-mode)

• Low latency applications › Hollow core loss not acceptable for low latency applications

› No new amplifier huts can be installed

A story is needed based on cost / bit with a smooth upgrade scenario

M. Kuschnerov 11


Gradual system upgrade scenario

M. Kuschnerov 12

• New transponders, amplifiers and ROADMs are single-mode and multi-mode capable

• Legacy transponders can run over multi-mode equipment without degradation

• N modes are run either on N SSMFs or groomed together on a multi-mode fiber

Backwards compatibility of SDM equipment allows a gradual upgrade scenario

nx mode-1Tb/s

nxROADM Terminal

Terminal

Single-mode

amplifiers

Multi-mode

amplifier

mxROADM

100G

nx-1T

nxSSMF

nxSSMF

nxSSMF

nxSSMF

Multi-mode

fiber

nxSSMF

nxROADM nxROADM

MU

X D

MU

X


Scenario 1: Legacy interoperability of SDM

M. Kuschnerov 13

• Demonstrated over 1,247km of transmission in a live network (SSMF, TWRS, MMF)

• No additional penalty of multi-mode equipment compared to single-mode transmission

ROADM Terminal

Terminal

Multi-mode

amplifier

ROADM

SSMF

SSMF

Multi-mode

fiber

SSMF

ROADM ROADM

Coriant 100G


Scenario 2: nxSSMF MMF nxSSMF

M. Kuschnerov 14

• Demonstrated over 3 modes in combination with field-deployed SSMF

• 8QAM, 16QAM modulation formats

Terminal

Terminal

Multi-mode

amplifier mxROADM

3xSSMF

nxSSMF

3xSSMF

Multi-mode

fiber

3xSSMF

nxROADM nxROADM

MU

X D

MU

X

3x200G


Scenario 3: Multi-rate, multi-distance, multi-Tx

M. Kuschnerov 15

• Hybrid transmission demonstrated in interoperation with deployed live network

• Transmission over 1,247km (SSMF, TWC, MMF)

Terminal

Terminal

Multi-mode

amplifier mxROADM

3xSSMF

1xSSMF

3xSSMF

Multi-mode

fiber

3xSSMF

nxROADM nxROADM

MU

X D

MU

X

2x200G

1x100G


System cost modeling

Modeled components: Transponders, regenerators, ROADMs, amplifiers, shelves, fiber,

other

M. Kuschnerov 16

Single mode Multi-mode

Data rate 1Tb/s (QPSK) / 2Tb/s (8QAM / 16QAM)

Subcarriers 10 1 with 10 modes

Optics Int.10 transceiver Int. 10mode transceiver

Max. capacity / fiber (C-band) 50Tb/s 500Tb/s

Mux / Dmux WDM Mode multiplexing

DSP 1 chip with 10 parallel

subcarriers

1 chip with 10 combined

modes

ROADM Standard Single multi-mode ROADM

Amplifier Standard Single multi-mode amplifier

Fiber SSMF / PSCF Solid-core MMF, hollow core

MMF


Longhaul vs. metro-regio

1,000km vs. 3,000km link

• C+L band with Raman amplification

• Longhaul: 7 spans / node

• Metro-regio: 2 spans / node

• 20K€ / km fiber deployment costs

• 30% mark up for multi-mode if similar

technology

M. Kuschnerov 17


Total cost @ 1Pb/s

M. Kuschnerov 18

1,000km metro-regio link 3,000km longhaul link


Variation of fiber deployment costs

• Fiber deployment costs are

network / country dependent

• Options:

Aerial

Blowing in existing tubes

Digging for new trenches

• Verizon estimate (OFC 2013):

$18K-$30K

• Other estimates range from:

$15K-$300K

M. Kuschnerov 19


Owned vs. leased fiber

• Deployment costs depend on

whether the operator owns the fiber

plants

• Cost analysis without taking into

account fiber costs (assuming a

lease is already running)

M. Kuschnerov 20


Next steps

• Development of missing technologies › Isolators, circulators, gain flattening filters, all-mode couplers/splitters, mode converters, VOA, tunable

filters,

› Spatial wavelength selective switch

• Scaling of existing technologies › 10-mode multi-mode fiber with low DGD, low PDL

› Multi-stage 10-mode amplifiers with automated controls and longhaul performance

› 10-mode multiplexers

› Investigating the potentially lower nonlinearity of solid core multi-mode fibers

• Pushing cutting edge hollow core fiber development › Loss reduction

› Manufacturability

M. Kuschnerov 21

upgrade scenario for legacy systems and achievable system cost

Documents