Increasing Fiber Capacity with CWDM · • Lower CWDM Band = lower 10 CWDM wavelengths – “Standard/Legacy 1310” is a subset of Lower Band (1270nm to 1360nm.) • Upper CWDM

Increasing Fiber Capacity with CWDM

A Tutorial on CWDM Network Design

Presented by:

Greg Scott

MSO/Telecom Sales

Increasing Fiber Capacity with CWDM

Introduction

WDM Technology Overview

CWDM and Fiber Cabling

Multiplexing Equipment

Application Examples

Wavelength Conversion

Charter Examples

3© 2012 Omnitron Systems

About Omnitron Systems

• Founded in 1992

• Corporate Headquarters

in Irvine California

• Provides Carrier-Grade

Fiber Connectivity Solutions

for Utilities, Service Providers,

Enterprise and Government

networks

iConverter Products are MEF 9/14/21 and

NEBS Level 3 Certified.

iConverter ®

Intelligent Media Converters,

CWDM Multiplexers,

T1/E1 Multiplexers

and Network Interface Devices


MSO Challenges

Adding more Customers – Business and Residential

Adding more Services – Voice, Video and Data

Limited fiber resources

Expensive and time consuming to add more fiber

Stretching the Capacity of Fiber Infrastructure


Expanding Capacity of Fiber Networks

Three Options

1) Install New Fiber

• New links for each location/application/data type

• Expensive and time consuming installation

2) Protocol Converters / Aggregation

• Circuit Emulation converges the different applications into TDM or Ethernet

• Expensive and complicated equipment

3) Wavelength Division Multiplexing

Increasing Fiber Capacity with CWDMIncreasing Fiber Capacity with CWDM

Introduction






Charter Examples


Fiber Optic Communication

• A method of transmitting information from one place to another by sending pulses of light through an optical fiber

• The light forms an electromagnetic carrier wave that is modulated to carry information


WDM Overview

Wavelength Division Multiplexing

• Overlaying multiple wavelengths/colors on one fiber link

– Each wavelength is a secure and an independent data channel

– Each channel is protocol and speed transparent (up to 10 Gig)

– Increases the capacity of the fiber infrastructure

• Inexpensive when compared to the alternative solutions

• Implementation has little to no impact to existing network

– Legacy 1310nm or 1550nm network unaware of xWDM

wavelengths on same fiber


WDM Single Fiber

Single-Fiber utilizes Bi-Directional (BIDI) WDM technology

1310nm

1310nm

Dual Fiber utilizes one wavelength over two strands of fiber

Two independent wavelengths

over one strand of fiber

Rx

Tx

Tx

Rx

Tx / Rx Rx / Tx

1310nm

1550nm


WDM Technologies

Dense Wave Division Multiplexing

Course Wave Division Multiplexing

“Grey wavelength”


DWDM and CWDM

DWDM

• DWDM systems use temperature-controlled lasers with

narrow-band filters

• 1nm wavelength spacing or less with up to 160 wavelengths

• Widely implemented in long-haul optical networking


DWDM and CWDM

CWDM

• ITU-T G694.2 specifies 18 wavelengths between

1270nm to 1610nm in 20nm increments

• CWDM uses non-stabilized lasers with broadband filters

• Cost effective solution for increasing capacity of Enterprise,

Municipal and Service Provider Metro/Access networks

• Number of wavelengths appropriate for these applications


DWDM and CWDM: L-TWC vs L-Charter

Some Observations

• L-Charter more likely to deploy DWDM and L-TWC more

likely to deploy CWDM (esp business applications)

• But both use CWDM and DWDM mix today

• Main reason CWDM persists is cost.

• As DWDM optics drop in price we’ll see less CWDM.


• WDM technology enables a fiber optic cable to carry multiple Wavelengths (Lambdas)

• Each Wavelength is an independent data Channel that can transport any network protocol or data rate

• Additional Channels can be added if the Wavelengths are unique

1470nm

1490nm

1510nm

1530nm

Common Line

MUX MUX

WDM Overview


CDWM and Standard/Legacy Wavelengths

• Standard 1310nm or 1550nm have wider tolerances and

utilize more of the spectrum than CWDM wavelengths

• Standard wavelengths can be used in conjunction with the

CWDM wavelengths (through Pass Band ports)

• Standard wavelengths are not precise enough for the 20nm

filters used in CWDM multiplexers

• Standard wavelengths can be converted to CWDM

wavelengths with Transponders or SFPs

Standard

1310

Standard

1550

16

CWDM expands the capacity of existing fiber infrastructure

Unused

The Fiber Optic Highway

with one standard λ

1610 nm

1310 nm

1390 nm

1270 nm

1370 nm

Unused

1470 nm

1490 nm

1510 nm

1530 nm

1610 nm

1550 nm

1570 nm

1590 nm

1310 nm

1330 nm

1350 nm

1370 nm

1450 nm

1390 nm

1410 nm

1430 nm

The Fiber Optic Highway

with CWDM λ’s

1290 nm

1270 nm


CDWM Wavelength Band Allocation

Different “Bands” – or groupings of wavelengths• ITU Bands – 5 bands defined by ITU

• Lower CWDM Band = lower 10 CWDM wavelengths– “Standard/Legacy 1310” is a subset of Lower Band (1270nm to 1360nm.)

• Upper CWDM Band = upper 8 CWDM wavelengths– Group 1 (1510, 1530, 1550, 1570) commonly used for CWDM MUXes

– Group 2 (1470, 1490, 1590, 1610) compliments Upper 1

Lower 10 CWDM Upper 8 CWDM

O Band C BandE Band S Band L BandITU Bands

Group 1 Group 2Group 2


Introduction






Charter Examples


Definition of Terms

Attenuation / Optical loss

• The rate at which an optical signal decreases in intensity

Dispersion

• The spreading of light pulses as they travel through fiber optic cable.

• Dispersion results in distortion of the signal, which limits the bandwidth and distance of the fiber

Optical Power Budget

• The difference between the minimum transmit power and the minimum receiver sensitivity of the optical devices connected across a fiber optic link.


Fiber Types for CWDM Applications

Single Mode Fiber is required for CWDM

– Multimode not recommended

Types of Single Mode Fiber

• Non-dispersion-shifted (NDSF), G.652, G.652.C & G.652.D– Most common (see next slide)

– Dispersion minimized at 1310nm

• Dispersion shifted fiber, G.653– Not commonly deployed

– Dispersion minimized at 1550nm

• Non-zero dispersion-shifted fiber (NZ-DSF), G.655 – Developed to minimize issues (nonlinear effects) in DWDM systems.


Optical Loss vs Wavelength

Loss

(dB/km)

nm1300 1400 1500 1600

1.0

0.9

0.6

0.3

0

G.652G.652C

Water Peak

G.652D

Minimized

Dispersion


Fiber Types for CWDM Applications

1) Know the type of fiber installed in your network• Contact the manufacturer

• Test your fiber links

2) Plan accordingly• Determine the areas of the spectrum that have the highest

attenuation in the fiber link

• Use the optimum attenuation areas of the CWDM spectrum

in your design


Optical Loss

There are many factors that can result in optical

signal loss in a CWDM network…– Fiber loss (depends on length and type of the fiber used)

– Passive device insertion loss (CWDM MUX and CWDM

OADM)

– Connectors (couplings)

– Patch panels and splices

When calculating optical loss …– The total loss plus safety factor (typically 3dB) must not exceed

the optical power budget.

– The optical power budget is calculated by subtracting the

minimum receive sensitivity from the minimum transmit power.


Optical Loss – Example A


Optical Loss – Example B


Introduction






Charter Examples


CWDM Multiplexers

CWDM MUXes are Passive Devices

• CWDM Multiplexers modules do

not require power to operate

• Pass all data channels

transparently

• Support data rates up to 10 gig

per channel


Channel 2

Channel 3

Channel 4

Channel 1

Types of CWDM Multiplexers

Channel Ports (Upper 1)

1510nm (Tx)

1530nm (Tx)

1550nm (Tx)

1570nm (Tx)

Common (Rx)

Common (Tx)

1510nm (Rx)

1530nm (Rx)

1550nm (Rx)

1570nm (Rx)

Individual MUX and DMUX Modules

Vs. Integrated MUX/DMUX Module – higher density

MUX

DMUX

MUX/DMUX


Types of CWDM Multiplexers

Dual Fiber and Single-Fiber

1510nm

1530nm

1550nm

1570nm

Common

4 Channel Dual Fiber

1510nm1530nm

1550nm1570nm

Common

2 Channel Single-Fiber

Single-Fiber MUXes support 1/2 the Channel Ports of Dual Fiber MUXes

because each channel is 2 wavelengths (BIDI) over the Common Line.

Each Channel is 1 Wavelength

Each Channel is 2 Wavelengths


Types of CWDM Multiplexers: OADM

Multiplexers are used at each end of a CWDM Common Line

to MUX and DMUX wavelengths





Optical Add+Drop Multiplexers (OADM) are used to insert

(add) and remove (drop) wavelengths at any point along a

CWDM Common Line





Optical Add+Drop Multiplexers (OADM) are used to insert

(add) and remove (drop) wavelengths at any point along a

CWDM Common Line


Definitions

Channel Port

• A port for a specific CWDM wavelength

Common Port

• A port for the CWDM Common Line that transmits/receives

all multiplexed wavelengths

1310 Pass Band Port

• A port which connects directly to communications equipment

and enables standard/legacy 1310nm wavelength to pass

transparently

• Examples:– Modulated analog signal / broadcast TV

– 10GBASE-LR Ethernet

– OC3/12/48 SONET


Port Definitions

Expansion Port

• Cascades multiple MUX/DEMUX modules, e.g.: cascading two 8-Channel MUX modules yields 16 channels

• Can also function as a 1550 Pass Band port

• Also called an Upgrade Port or Express Port


1310 Pass Band Port

MUX/DMUX 4-Channel Dual Fiber Modules

Upper CWDM Band

with 1310 Pass Band portChannel 1 1510nm

Channel 2 1530nm

Channel 3 1550nm

Channel 4 1570nm

Common Port


CWDM

MUX/DMUXCWDM

MUX/DMUX

1510nm

1530nm

1550nm

1570nm

1310 PB

Channel Ports

MUX/DMUX 4-Channel Dual Fiber Modules

Dual Fiber

Common (Rx)

Common (Tx)

Common (Tx)

Common (Rx)

4-Channel MUX/DMUX at each end of a dual fiber

Common Link provides four independent data paths,

plus a 1310 Pass Band (PB) channel that

connects directly to legacy equipment.

Channel Ports

1510nm

1530nm

1550nm

1570nm

1310 PB

4-Channel Dual Fiber

with Pass Band


MUX/DMUX Application Example

4-Channel Point-to-Point MUX/DMUX with 1310 Pass Band

Four new data channels added to existing fiber link

carrying existing 1310nm data.

Legacy 1310 device can be Ethernet, SONET,

TDM or other protocol.



• HFC Network

• Overlay CWDM channels for new Business Services


1310 Pass Band Port

MUX/DMUX 4-Channel Dual Fiber

Upper CWDM Band

with Pass Band port

and Expansion port

Channel 2 1490nm

Channel 4 1610nm

Common Port

Channel 1 1470nm

Channel 3 1590nm

1510-1570 Expansion Port



4-Channel Point-to-Point MUX/DMUX with Expansion

1310

Pass Band


4-Channel Point-to-Point MUX/DMUX with EXP and PB


Expansion Port can also be used as a 1550 Pass Band Port.

Pass Band Port can also be used for a Management Channel.

Legacy 1550

Expansion

(1550 Pass Band)

Upper 2 Band

1310

Management

Channel



Upper CWDM Band

Channel 5 1490nm Channel 6 1610nm

Common Port

Channel 1 1470nm Channel 2 1490nm

Channel 7 1610nm

Channel 3 1510nm

Channel 8 1610nm

Channel 4 1530nm



Upper CWDM Band

1310 Pass Band portChannel 5 1490nm

Channel 6 1610nm

Common Port

Channel 1 1470nm

Channel 2 1490nm

Channel 7 1610nmChannel 3 1510nm


1310 Pass Band



Lower CWDM Band Channel 2 1350nm

Channel 4 1370nm

Common Port

Channel 1 1270nm

Channel 3 1290nm



?Water

Peak!


Application Example

8-Channel MUX and Two 4-Channel Drops

using an Expansion port

The Expansion Port also enables a cascade port to another location


OADM Modules

Optical Add+Drop Multiplexers enable CWDM channels to

be added and dropped along a CWDM Common Line

1-Channel Dual Fiber OADM 2-Channel Dual Fiber OADM


OADM Example

Cell Tower Backhaul


Right Common Port

(Passed Wavelengths)

Channel 1 Left 1590nm

Left Common Port

(Passed Wavelengths)Wavelengths pass through both

(Left & Right) Common Ports

Channel 1 Right 1590nm

OADM Modules

1-Channel Dual Fiber OADM

Select Wavelength

for Add + Drop

1590nm is extracted

out and inserted in

Lower Band OADM Upper Band OADM


CWDM MUXCWDM MUX

Dual Fiber, Single-Channel OADM

OADM

1570nm (Tx)

1570nm (Rx)

1510nm (Tx)

1530nm (Tx)

1550nm (Tx)

1570nm (Tx)

1510nm (Rx)

1530nm (Rx)

1550nm (Rx)

1570nm (Rx)

Channel Ports

1510nm (Rx)

1530nm (Rx)

1550nm (Rx)

1570nm (Rx)

1510nm (Tx)

1530nm (Tx)

1550nm (Tx)

1570nm (Tx)

Channel Ports

Common (Rx)

Common (Tx)

Common (Tx)

Common (Rx)

1570nm (Tx)

1570nm (Rx)

A dual-direction OADM Adds and Drops a wavelength along the Common fiber route in both directions

Channel

Left Port

Common

Left PortCommon

Right Port

Channel

Right Port


OADM Application Example

1 Channel OADM with Dual Direction Add+Drop

The 1570nm Channel can be Single Direction (D)

E). or Dual Direction (D & E).


Right Common

(Remaining Wavelengths)

Left Common

(Remaining Wavelengths)

Select Two Wavelengths

for Add + Drop

CWDM OADM Modules

2-Channel Dual Fiber OADM Channel 1 Left 1510nm


Channel 2 Left 1530nm


Lower Band OADM Upper Band OADM


OADM & MUX/DMUX Application Example

Bus (Linear) Topology with 1-Channel and 2-Channel

Add+Drop locations using the Upper 2 Band

A single-direction OADM is used at each location.

Note the higher wavelengths utilized for longest distances due to lowest attenuation.


OADM Ring Application Example

Dual Fiber Resilient Ring with 1 and 2-Channel Add+Drops

OADMs used to Connect and Bypass Switch Nodes.

Many more networks and nodes can be added to the ring.


Section Summary

• CWDM is Cost Effective– Much less expensive than upgrading switches and routers

– Maintain investments in existing equipment

• Rapid Deployments– Passive equipment that is easy to use

– Plug and play installations

– No disruption to existing services (Spanning Tree and SONET)

• CWDM Multiplexers Support Dual and Single-Fiber– Single Fiber MUXes support ½ the channels of Dual Fiber.


Section Summary

• Wavelength Band Allocation Provides Design Flexibility– Enables Passing of Standard/Legacy 1310nm and 1550nm

– Complementing Bands for Expansion Ports

– “Workaround” for the 1400nm Water Peak

• MUXes and OADMs Provide Flexible Designs – Add and Drop Linear Bus applications

– Pass Band Ports enable overlaying CWDM onto existing networks

– Overlay Channels on SONET and Resilient Ring networks

– Expansion Ports provide flexibility for future growth

– Expansion Ports also double as 1550 Pass Band,

and enable passing channels to different locations

– Both MUXes and OADMs can be used to Connect and Bypass

Nodes on ring networks


Introduction






Charter Examples


CWDM Wavelength Conversion

OK, CWDM is cool stuff.

But how do I connect my equipment to CWDM MUXes?

• Small Form Pluggable (SFP) transceivers

• Transponders / Wavelength converters

• Media Converters that support SFPs


How to Connect Legacy Equipment to CWDM Networks

• Small Form Pluggable (SFP) transceivers

are compact interchangeable connectors

• CWDM SFPs support 18 ITU-T G694.2 wavelengths

between 1270nm to 1610nm in 20nm increments

• Omnitron color codes latch handles in Upper Band


Wavelength Color

1610nm Brown

1590nm Red

1570nm Orange

1550nm Yellow

1530nm Green

1510nm Blue

1490nm Purple

1470nm Gray


How to Connect Legacy Equipment to CWDM networks

• CWDM SFPs are used with SFP capable switches to

convert standard wavelengths to CWDM wavelengths





• Transponders are Fiber-to-Fiber converters with SFPs

that convert standard wavelengths to WDM wavelengths

• Also converts Multimode Fiber to Single-mode Fiber

iConverter xFF iConverter XG




• Transponders convert fixed fiber ports with legacy

wavelengths to CWDM wavelengths




• Media Converters that support SFPs enable connectivity

between copper equipment and CWDM networks

• Support a wide variety of network protocols, cabling and

connector types

iConverter managed media converters with pluggable transceivers




• Media Converters with CWDM SFPs convert copper to

fiber with CWDM wavelengths


CWDM Wavelength Conversion – Summary

To multiplex data channels, each wavelength from the network

device must be converted to appropriate CWDM wavelength

CWDM MUX

1510nm

1530nm

1550nm

1570nm

+

Transponder CWDM SFP

(SM 1530nm)

ATM Router Standard SFP

(MM 1310nm)

+Fast-E switch (UTP) 10/100 Media Converter CWDM SFP

(1550nm)

CWDM SFP

(1510nm)+

Gig-E switch w/SFPs

T3 MUX

+T3 Media Converter CWDM SFP

(1570nm)


Introduction






Charter Examples

TWC vs Charter: Commercial

TWC CHARTER

1431

1451

1471

1491

1511

1531

1551

1571

1591

1611

1310 PB

COM

OTDR

1431

1451

1471

1491

1511

1571

1591

1611

1310 PB

COM

8 channel DWDM (ITU 28 to 35)

TWC Business Class typically

used all CWDM

Charter Business used CWDM or

CWDM + DWDM

67 Proprietary and Confidential © 2017 Omnitron Systems

DWDM over CWDM

3.

4

3.

7

Insertion loss

OP34 2.9dB

Chan to common 3.7

dB

Com to exp 3.4 dB

TWC Business Class: Regional Variations

Carolinas and CA use 10 channel

single fiber

Texas, KC, others, uses mostly 8

channel dual fiber

TWC vs Charter: Residential Node Splits

Corwave 1 LcWDM

Downstream (O-Band)

1290,1291,1293,1295

Return Path

1471,1491,1591,1610

Downstream (O-Band)

KK LL MM NN RR SS

Return Path

1471,1491,1591,1610

Both of these use unusually spaced proprietary “O-Band” CWDM

Omnitron Product SlidesOmnitron Product Slides


iConverter CWDM Product Summary

Dual Fiber Products:• 4 and 8 Channel MUX/DMUX

• 1 and 2 Channel OADM

Single-Fiber Products:• 2 and 4 Channel MUX/DEMUX

• 1 Channel OADM

Multi-Service Platform• Ethernet, Serial & TDM over Fiber

• Modular and Compact Chassis

System


iConverter Multi-Service Platform


CWDM Resource CenterVisit www.omnitron-systems.com

▪ CWDM Design Guide

▪ Video CWDM Presentation

▪ Case Study

CWDM Network Design SupportContact Greg Scott

[email protected]

949-250-6510 ext 8135

949-278-0908

Additional Resources

mailto:[email protected]


USA

Phone: 949-250-6510, Ext. 8135

Toll Free: 800-675-8410

Email [email protected]

Web www.omnitron-systems.com

Omnitron SystemsSales and Support Contact Information

Q and A

Thank You!

Greg Scott

[email protected]

949-250-6510 ext 8135

949.278.0908 m

Documents

Increasing Fiber Capacity with CWDM · • Lower CWDM Band = lower 10 CWDM wavelengths – “Standard/Legacy 1310” is a subset of Lower Band (1270nm to 1360nm.) • Upper CWDM