Why Choose Optical Fibre Instead of Copper Cables

1
Why Choose Optical Fibre Instead of Copper Cables?

• Russell Ellis PhD
• Corning Optical Fiber
• Senior Applications Engineer
• 1215pm March 8, 2006

2
Why Choose Optical Fibre Over Copper Cables?

• Higher Bandwidth
• System Performance
• Installation Considerations
• Ease of optical fibre
• Complexity of copper cables
• Network Cost Modeling
• UTP and Fibre Networks
• Fibre Specifications
• Laser Optimized Fibre
• Transceivers
• Fibre Costing Modeling
• MMF vs SMF
• Summary

3
Higher Bandwidth
50/125 Multimode fibre (850 nm)
CopperCable
10000
One generation of MMF outlived 4 generations of
UTP
1000
100
Bandwidth (MHz.km)
10
CAT 7
CAT 6
CAT 5
CAT 5e
1
CAT 3
0.1
1985
1990
1995
1999
2002
2005-6
Year
Evolution of relative bandwidth-reach (MHz.km)
performance of copper cabling vs 50/125 multimode
fibre optical fibre over time
4
System Performance
Reach capability of fibre vs copper cables at
1Gb/s and 10 Gb/s
Optical fibre
OM-3
OM-3
OM-2
OM-1
Copper Cable
System Cabling
CAT 7
1Gb/s
10 Gb/s
CAT 6
CAT 5e
0
200
400
600
800
1000
1200
System Reach (meters)
Note MMF link distances are quoted for 850 nm
operating wavelengths
5
Installation Considerations

• Despite the complex nature of optical fibre
  technology, Laser Optimized fibres are easy to
  work with

6
Optical fibre cables are easier to install

• Smaller size and consequently lighter weight
  cables are more practical and easier to route in
  confined spaces
• A typical duplex fibre cable is up to 40 smaller
  than a CAT-6 (UTP) cable
• A typical 24F optical fibre cable is roughly the
  same size as a CAT-7 cable
• For approximately the same diameter a 24F OM-3
  cable can support12x more bandwidth, 240 Gb/s
  (Duplex) and able to reach up to 300m
• Optical cable design is not restricted to fibre
  type

CAT-7 (STP)
12x Duplex Fibre (24 fibre cable)
Duplex Fibre (2 Fibres)
CAT-6 (UTP)
7
10GBASE-T

• Technical Hurdles
• 2.5 Gb/s per twisted pair across 500 MHz
  frequency range
• CAT6 legacy cable tested to 250 MHz
• Digital signal processing (DSP) for internal
  noise cancellation
• eliminate the effects of cross-talk between pairs
  of cable and the effects of signal reflections
• EMI Noise Ingress
• Heat Dissipation (8-10W/port)
• Reduced Blade Density
• 6-8 ports per blade (copper)
• 16-18 ports per blade (optical)

8
10GBASE-T Cable Noise
9
10GBASE-T Alien Cross Talk

• Main electrical parameter limiting 10
  Gigabit Ethernet performance over copper UTP
  cable
• Cannot be corrected with electronics
• 20dB suppression required over 100m
• Cable and patchcord separation
• Wider port separation on patch panel
• Cable electrical Specifications defined by IEEE
  and passed to TIA for adoption into augmented
  CAT6e.
• CAT6e only UTP cable with alien cross-talk
  guidance
• Not backward compatible to other UTPs

10
10GBASE-T Alien Cross Talk

• PSANEXT measured in controlled lab
• Six around one configuration
• No reliable field measurement capability to date
• Interoperability issues with pre Standard cable
  solutions
• Larger cable
• Larger jack
• Larger plug
• Reduced port density on patch panels
• 1U 24 ports

11
Installation Cable routing considerations

• The dielectric nature of optical fibre cables and
  EMI immunity enables increased flexibility
• Copper UTP cables generate and are sensitive to
  EMI
• At high data rates UTP cables generate more RF
  interference
• To avoid alien cross-talk problems UTP cables are
  required to be separated or S-routed in channels
• Coupled with the larger diameter this can choke
  channels and ducting areas and reduce the airflow
  needed for cooling in Data Centre applications

Optical Fibre cables can be densely routed In
channels
UTP cables require spacing toreduce cross talk
penalties
12
Fibre connectivity trends

• Pre-terminated solutions 75 faster
  installations than traditional cabling solutions
• Attractive for high port density applications
  such as data centres
• Coded connector and patch-panel increase security
  
• Modular component design facilitates moves,
  adds and changes
• Small-form-factor products (LC, MT-RJ, MTP,
  ribbon cable) reduce space needed under floor,
  overhead and in racks/cabinets

• Pre-terminated cable
• 72F Small diameter cable
• 6 MTP terminations

13
Post Network Cabling Installation On-Site Testing
and Certification

• MMF for Premises Networks
• Factory Measured BW, Attn etc.
• MMF SMF Insertion loss measurement, even for
  10Gb/s
• Copper cables increasingly more complex to work
  with
• Requiring a number of tests
• UTP sensitive to EMI and cross-talk issues
• Automated test equipment can reduce time
• Copper data more difficult to interpret if one or
  more test criteria not met

Post Installation Testing For copper cables
fibre
16
14
Optical Fibre
12
Copper Cable
10
Individual certification tests
8
6
4
2
0
1980
1992
1995
2002
2006
Year
14
Optical Fibre vs Copper Cables in Premises
Application Space

• Horizontal
• 99 Copper
• 10/100/1000 Mb/s

• Riser
• 80 MMF/20 Copper
• 25 1Gb/s
• 75 100 Mb/s

• Campus/Inter-building
• 95 fibre
• and increasing
• 50 1Gb/s
• 50 100Mb/s
• single-mode fibre for long distance

• Data Centers
• 50 fibre and increasing
• 1, 2, 4 and 10 Gb/s
• Fibre is winning, MMF is winning

Source Corning Optical Fibre/Corning Cable
Systems Analysis
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Installation Summary

• Optical fibre is increasingly easier to install
  and test
• Field installable connectors offer flexibility
  and pre-terminated solutions are faster and
  easier to work with
• Optical fibres offer an easier upgrade path
• Overlay optical cables have no interference or
  operational impact on existing copper or fibre
  infrastructure
• OM-3 grade multimode can theoretically support up
  to 40Gb/s100Gb/s using parallel optics
• Copper cables are becoming more difficult to
  install and test
• UTP cables at high data rates require spacing to
  reduce cross-talk effects
• Increased spacing at the connector reduces port
  density
• STP copper cables require grounding increased
  complexity and testing requirements

16
Cost breakdown passive/interfaceOptical Fibre
Networks
Typical Component Cost Breakdown

• Electronic systems costs dominate
• Transceiver selection/cost important
• Depends on fibre type
• Cable infrastructure cost is small
• Longest life cycle
• Dictates current and future bandwidth capacity
• System Reach Capability
• Big bearing on operating costs
• Flexibility
• Upgrade options

Source Corning Optical Fiber/Corning Cable
Systems Analysis
17
Copper Cable Interfaces

• Shorter reach of copper solutions require greater
  number of telecommunication or equipment rooms
  (TR/ER) in larger buildings
• Typically one TR/ER per floor in multi-storey
  building
• Whilst copper cables are cheaper than optical
  fibre cables, longer reach capability of fibre
  can reduce other associated costs
• Copper interfaces 1Gb/s increasing require
  signal processing to recover transmission quality
• Increased complexity
• Higher signal attenuation of copper at high
  frequencies
• May result in higher power consumption
• Higher burden on cooling equipment
• Port density may be affected

18
Cost Modelling Private Networks

• Cost model analysis of 3 different network
  topologies for PNs using fibre and copper
  structured cabling
• Hierarchical Star Network Design
• UTP copper used in horizontal cabling
• Fibre used in the riser/vertical cabling only
• Centralized Fibre Network
• Fibre rich network
• Fibre-To-The Desk (FTTD) type architecture
• Fibre-To-The-Enclosure (FTTE) Network(low high
  density designs)
• Fibre home runs to smaller telecom enclosures
  on each floor of the building
• UTP copper cable connection to the User

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Premises Network TopologiesHierarchical Star
Network
Fibre
Copper
Cat 6 Patch Panel/cords
Cat 6 Cabling
Workgroup switches
Fibre patch Panel/cords
Telecom Room (TR)
8th Floor
1st 7th Floor (typical)
Core Switch 1000BaseSX B/B 1000 BaseTX Server
Ports
Patch Panel
Main Equipment room
Main Floor
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Premises Network TopologiesCentralized Fibre
Network (FTTD)
Fibre
Copper
Fibre Cables
Splice/connect (not required if W/S with NIC Media Converter
Telecom Room (TR) (smaller rack/wall enclosure)
8th Floor
High fibre count riser
1st 7th Floor (typical)
Core Switch 1000BaseSX B/B 1000 BaseTX Server
Ports
Patch Panel
Workgroup Switches
Main Equipment room
Main Floor
21
Premises Network TopologiesFibre-To-The
Enclosure Network
Fibre
Copper
Optical Fibre
Patch Panel
Fibre Cables (no splice or Interconnect Needed)
min-Switch
Patch Panel
Telecom Enclosure
8th Floor
1st 7th Floor (typical)
Core Switch 1000BaseSX B/B 1000 BaseTX Server
Ports
Patch Panel
Main Equipment room
Main Floor
22
Comparative Network Costs

• 8 Floor Building PN
• 54 Ports/floor
• Copper cable
• Cat 6 UTP and 1000BaseTX
• Optical Fibre
• 50/125 (OM-2) Fibre
• 1000BaseSX Transceivers
• Hierarchical Star Network
• UTP Horiz./MMF Riser
• ER costs 50 total
• Centralized Fibre Network
• Cabling Switch electronics 50 cost
• FTTE (High Density)
• Lowest Cost
• FTTE (Low Density)
• Cabling Switch electronics 50 cost

Calculated Network Installation Costs
Desk Hardware
Cabling and Electronics
ER Install Running Costs
Labour costs
ER Cabling Equipment
300K
250K
200K
150K
100K
50K
0
Hierarchical Star Network
FTTE (HD) Network
FTTE (LD) Network
Centralized Fibre Network
Source Corning Optical Fiber/FOLS Interactive
Cost Model
23
10Gb/s Operating CostsOptical vs. Copper
Fiber
Copper
Power Consumption
2W
8-15W
Cooling Requirements
Transceiver Size


Data Center Area
24
Cost Modelling Summary

• Significant cost differences in between copper
  and optical fibre components
• Fibre based networks can cost less than copper
  based networks when designed around the intrinsic
  advantages of fibre
• Higher associated costs of active equipment for
  copper cables
• Equipment Rooms Costs
• Higher Power Consumption
• Increased Cooling
• Other system/operating costs, UPS, etc.
• Optical fibre cables have a longer life cycle
  than copper

25
Standard Optical Fibre Types for Premises Networks
Laser Optimized fibre types recommended
Notes regarding BW measurements 1 As predicted
by OFL BW, per IEC 60793-1-41, for legacy and
LED-based systems (typically up to 100Mb/s) 2 As
predicted by RML BW, per IEC 60793-1-41 for
intermediate performance laser-based systems typ.
Up to 1Gb/s 3 As predicted by minEMBc, per IEC
60793-1-49, for high performance laser-based
systems up to 10Gb/s 4 550m link distance
achievable with cabled fibre attenuation
3.0dB/km and 1.0dB total connector loss
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Laser Optimized multimode fibres can assure high
performance with Lasers
Light Sources
Bandwidth Measurement

• OFL (Overfilled-Launch)
• Designed to predict performance of low-speed
  LEDs, not lasers
• Power distributed in 100 of the fibre core, like
  LEDs
• Perturbations in index profile undetected
• Laser-Based Measurements
• EMBc laser based BW technique with DMD
  (Differential Mode Delay)
• RML (Restricted Mode Launch) or Power
  distributed in a narrow region
• Simulates an actual laser launch
• More accurate indication of performance in
  high-speed laser-based systems

(Typically 10 and 100 Mb/s)
(1, 2, 4, 8, 10 Gb/s and higher)
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Legacy OFL bandwidth measurements cannot predict
laser performance
Source TIA FO-2.2.1 Round Robin
28
Comparison Spectral Characteristics
Wavelength
LED
60 nm
Typ. 1300nm

l
4 nm
Fabry-Perot Laser
1310 nm

Higher Performance
3-10 dB
850 nm
VCSEL

0.1 nm
1550, 1310 nm
DFB laser
30dB

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Laser Optimized OM-3 SolutionLower-cost than LX
(1300 nm)
Assumptions

• 300m, 24F count cable, 24F Passive Interconnect
  (x2), 18x 1 Gb/s Transceivers

System Solution Options

• OM-2 fibre with SX transceivers
• OM-3 fibre with SX transceivers
• OM-2 fibre with LX transceivers
• Single-mode fibre with LX transceivers

SX solution saves up to half the cost LX
option And OM-3 5 overall cost increase
30
OM-3 OM3 Lower-cost than SMF over 300m
Assumptions
Relative System Cost 10 Gb/s 300m

• 300m, 24F count cable, 24F Interconnect hardware
  (x2),18x 10 Gb/s transceivers

1.4
1.3
1.2
System Solution Options
1.1
Relative Cost

• OM-3 fibre cable with 850nm VCSELs
• OM-3 fibre cable with 850nm VCSELs
• Legacy OM-1 fibre cable with WWDM 10 GBASE LX-4
  1300nm lasersand mode-conditioning patch-cords
• Single-mode fibre cable with 1300nm LR
  transceivers

1.0
0.9
0.8
OM-3
OM-3
OM-1
Single
-
Mode
-
1300 nm 10GBaseLX4
1300 nm 10GBaseLR
850 nm 10GBaseSX
850 nm 10GBaseSX
Note Figures based on Corning conservative
estimates
31
OM-3 Fibre Enables Higher Insertion Lossand
Extra Operating Margin
10Gb/s Serial Power Budgets (850nm) Using
standards complaint 10GBASE-SR Transceivers
8
7
Extra Sparemargin
Spare margin
6
Other penalties
Higher Penalties Over Longer distance 550m
5
ISI penalty
4
Total connector loss
Power Budget (dB)
Cable attenuation
3
2
Channel Insertion loss
1
0
OM-3 fibre
OM-3 (550m) fibre
OM-3 (550m ) Fibre
300 meters
300 meters
550 meters
Power budget calculations based 10Gb/s IEEE
model Cable attenuation is 3.5 dB/km, total
connector loss 1.5 dB Max cable attenuation 3.0
dB/km, 1.0 dB total connector loss
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Benefits of Optical Fibre

• Higher data rates and longer link lengths
• Flexible, reliable networks with low latency
• Unparalleled network security
• Immune to EMI, RFI and cross-talk
• Small lightweight cables maximizes pathway and
  space utilization
• Higher port density
• Easier installation, handling and termination
• Simplified field testing
• Longer cable life cycle
• Lower power consumption, less expensive to operate