Page1of18

HEXATRONICFIBEROPTICSOLUTIONSFOR

BROADBANDACCESSNETWORKS.

Page2of18

Introduction

In today’s world of broadband communications and services, fiber optics is the highest

performance, most reliable technology for high speed communications networks. The concept of

communicating using beams of light dates from 1880 when Alexander Graham Bell

demonstrated the Photophone.1 Since then, the history of fiber optics communications is a

fascinating example of technology development. Building on developments nearly a century

later when Corning developed low loss optical fiber, the first network using single-mode fiber

optics at bit rates greater than 1Gbps was successfully launched in the late 1980s. With

advances in laser transmitters and the development of optical amplifiers, today’s long distance

systems operate with capacities of thousands of Gigabits per second spanning continents and

oceans.

With the commercial growth of the Internet the bandwidth of the physical access network

providing network connections to individual homes and businesses became inadequate to

provide users with the benefits of rapidly expanding Internet services. Even after fiber optics

became a standard technology for telecom networks, it was still too expensive for connections

to individual subscribers. Not until the late 1990s, as costs trended downward, the first

deployment of fiber optic networks providing communications services to individual homes was

initiated.

Since these first deployments, the cost of fiber optic components has continued to drop as

production volumes increased by many orders of magnitude and newer device designs and

manufacturing techniques have replaced the initial fiber optic devices used twenty years ago. In

fact, today the cost of providing a fiber optic access network in greenfield installations can be

less than the cost of a conventional “copper” network with 70-75% of the cost coming from fiber

optic cables and construction labor for the Outside Plant (“OSP”). This places the primary focus

on the materials cost and the labor cost required to construct the network.

1 The Photophone transmitted sound waves on a beam of light. Bell considered it his most important invention.

Page3of18

This white paper will present the Hexatronic system solutions for FTTH networks showing how

the design and function of these products naturally lower OSP costs and shorten construction

schedules. Although, the focus will be on FTTH networks, the Hexatronic product advantages

also apply to rapidly emerging penetration of fiber optics for access networks to Multiple

Dwelling Units (“MDU”) such as apartment buildings, Office Buildings, and Campus installations,

such as universities, government facilities an industrial parks.

The Hexatronic Products Advantage

Hexatronic Cables and Interconnect Systems designs, manufactures and markets a complete

system solution for building fiber access networks. The Hexatronic products are purpose-

designed to provide the industry’s lowest Total Cost of Ownership (“TCO”) over the life of the

network. With world class customer support and a 20-year functional warranty, the Hexatronic

Advantage benefits all phases of fiber optic access network installation and operations.

including construction, installation of subscribers, network maintenance and repairs, and service

upgrades.

The most important financial advantage of the Hexatronic systems solutions can be the time

saved during the construction phase and the ease of bringing subscribers on line. This

generates revenue for the service provider sooner than possible with other equipment designs,

an important goal when the “time to market” for any new service will affect the financial success

of the investment in new networks and services. In other words, the payback from Hexatronic

products come not only during the construction phase but, through the timely launch of new

services.

Page4of18

Fiber Access Network Physical Design

A basic understanding of the design of a fiber optic access network will help understand the

application and advantages of the Hexatronic products. We will use a generic PON2 example in

this description. PON networks are the dominant network type in Fiber Access networks

because they minimize hardware cost by sharing some of the most expensive elements of the

OSP among a group of subscribers. Figure 1 shows a schematic layout of a PON network. The

PON network provides two-way communications over single fibers by using different

wavelengths for downstream and upstream signals, an important feature that lowers cost.

At the Service Office3, the Optical Line Terminal (“OLT”) connects between the local Metro

Network and the PON Network, providing the digital signal for the subscribers. It is located in a

2 PON is an acronym for Passive Optical Network, which describes the absence of any active devices between the Service Office and the subscribers. Two primary PON network designs are GPON and EPON. 3 We shall use “Service Office” to describe what could be a Central Office or Head End, depending on the service provider.

Figure 1 - The PON Network Structure

Page5of18

Service Office with many other OLT devices. Each OLT serves a single fiber with a high

capacity signal that serves multiple subscribers located as far as 20km from the Service Office.

The optical signal is transported in a fiber optic cable with as many as 192 fibers from OLT

devices.

Depending on the size of the network, there may be a Remote Terminal designed to extend the

reach of the equipment at the Service Office located closer to the service area.

At the Fiber Distribution Hubs (“FDH”) a passive fan-out optical splitter separates the signal into

typically 32 fibers4 that connect directly to individual subscribers.

At each subscriber, the Optical Network Terminal (“ONT”) is the optical transceiver that

connects to the optical network and interfaces with the subscriber’s computer, television,

telephone and other devices. The signals from multiple subscribers are combined in a separate

optical combiner at the FDH and delivered to the receiver port on the OLT, completing the two-

way high-speed connection from the home to the Metro network.

The passive splitter/recombiner function is the key defining feature of the GPON network. By

combining the digital signals for a group of subscribers into a single fiber, transporting the

signals over distances as high as 20km, and splitting the signal into individual fibers for each

subscriber, the materials cost of the fiber network is significantly reduced.

In a later section of this document, we shall see how the Hexatronic products are designed to

simplify the construction and activation of the PON network, saving both time and money.

The Hexatronic Fiber Access System

Hexatronic manufactures a complete systems solution product line of cables, ducts, duct joints,

cabinets, optical splitters, accessories and tools designed for all types of fiber access networks,

whether installed underground, in-building or aerial. These products are contained in the

Micronet micro cables system for the feeder and distribution portions of the network and the

Ribbonet® air blown fiber system for the drop network. Hexatronic system solutions give the

4 The splitting ratio of 32 is a typical value, but depending on the density of homes and geographic features, the split ratio can be as low as 8 and as high as 64. It is always a multiple of 2.

Page6of18

service provider flexible options to build out the network as service demand grows. Only the

fiber and splitters for actual subscribers are required, which saves money by not having to install

capacity before it is needed.

Micronet and Ribbonet Fiber Optic Cables

The Micronet fiber optic cables for the feeder and distribution networks are the heart of a fiber

access system connecting over long distances between the Service Office and the Fiber

Distribution Hubs. They provide the critical optical signal transmission with high signal quality,

reliability and consistency over the life of the network. As shown in Figure 2, there are different

designs with varying numbers of fibers providing the ability to design the network efficiently,

minimizing cost and construction schedules.

The micro cable technology offers important benefits when deploying the feeder and distribution

network. Hexatronic’s fiber cable designs are industry leaders offering a high fiber count in a

small cross section, enabling efficient installation in limited spaces.

Figure 2 - Hexatronic Micro Cables for Feeder and Distribution Networks

Page7of18

The Ribbonet® air-blown-fiber (“ABF”) system for installation in the drop network offers industry-

leading unique advantages in combination with the hand-held blowing tool and the unique

microducts designed for this purpose. The actual fibers are bend tolerant, which provides an

extra measure of reliability, especially for in-building subscriber premises networks. The

application and advantages of the Ribbonet® system are described in more detail later in this

document.

Microducts

The Hexatronic Microduct products are strong, miniature, flexible HDPE tubes with low inner

friction that protect fibers and fiber cables from dirt, moisture, animals and other damaging

Figure 4 Hexatronic Microducts for Feeder, Distribution and Drop Networks

Figure 3 - Ribbonet fiber in a spool and tray.

Page8of18

environmental factors when they are deployed, either underground or suspended on utility

poles. The Microduct products are compact size, with low internal friction, high strength and

resistance to severe environmental factors such as temperature and humidity. They come in

many varieties and sizes as shown in Figure 5.

Many microducts consist of a larger external protective shell with multiple smaller microducts

inside. These “multiducts” allow cost-effective provisioning with extra ducts for easy service

upgrades by blowing new fibers when necessary.

Duct Joint Closures

When installing the Microducts, a method of joining individual ducts together is needed that will

provide a tight seal against dirt, moisture, and all other environmental hazards. These joint

closures are available in many shapes and sizes, depending on the specific type of duct and the

geometry of the joint, whether end-to-end, right-angle branch or other. A selection of these parts

is shown in Figure 6.

Figure 5 - A Variety of Joint Closures for Microduct Products

Page9of18

Tools and Accessories

Various specialized tools for trimming ducts and fibers, joining ducts together and other uses

are provided in easy-to-use kits for field installation crews. Hexatronic recommends the use of

these tools, which are often specially designed to avoid damage to a cable or a duct that might

result from the use of an ordinary tool not designed for the specific task. An example of a set of

tools for blowing individual fibers from customer premises is shown in Figure 7.

Cabinets and Splitters

At different points in the network, where fibers must be joined together or to network

components such as the PON splitter, weatherproof sealed cabinets are used to manage the

Figure 6 - Hexatronic Ribbonet Tool Kit for Blowing Fiber from Customer Premises

Figure 7 Fiber Distribution Hub for 228 Subscribers and 32-way splitter on the right side

Page10of18

different components. Hexatronic manufactures enclosures with custom designed trays and

other fixtures that will protect the fibers from damage during the installation procedure and over

the life of the network. The design of these enclosures helps ensure that the process will be

error-free and can be performed efficiently. Hexatronic cabinet designs benefit from a history of

close cooperation with their customers and incorporating customer inputs into the design.

Installing the Fiber Access Network

The first step in the installation of a fiber optic access network is to create a network of suitable

ducts to contain the fiber optic cables. The ducts will be installed over the entire network

extending from the Service Office to the Fiber Distribution Hubs and beyond to every customer

site in the network.

After the ducts have been installed, the process of inserting the fibers in the ducts can begin. All

the required fibers for the feeder and distribution portion will be installed, but the choice of how

many fibers to install in the drop portion of the network will depend on the materials and tools

chosen for the project. The Hexatronic Ribbonet fibers and Microducts provide a unique

advantage in the drop network that minimizes cost and time for this portion of the construction.

Before discussing this issue, it is worthwhile to understand the technology for installing the fiber

cables into the ducts. This process is known as Cable Jetting.

Page11of18

Cable Jetting

In the early days of fiber optic system deployment, the fiber optic cables were pulled through the

ducts with a winch pulling a line attached to the end of the fiber cable. This method had many

problems due to the friction of the cable inside the duct, especially when pulling around bends.

Since the late 1980s, this method has been universally replaced by a technique known as cable

jetting invented by KPN Research based on techniques developed previously by British

Telecom. Cable jetting uses compressed air, in combination with a technique for pushing the

fiber optic cable into the duct to blow the fiber cable into and completely through ducts over

distances of a few kilometers. The friction problem is almost completely removed, because the

fiber cable rides on a cushion of compressed air flowing uniformly around the cable. The

distances that can be achieved with this technique are measured in kilometers and are

considerably longer than was achievable using pulling.

The cable jetting process is used in the feeder and distribution portions of the network,

extending to the FDH where the passive splitter is located.

Constructing the Drop Portion of the Network

When jetting the fiber cables into the feeder and distribution network, the number of fibers

needed can be forecasted accurately based on anticipated subscription rates averaged over

Figure 8 - Cable Jetting Tool and Operator

Page12of18

large areas, and the installation can proceed with negligible uncertainty about the overall design

and the number of ducts and fibers that will be required.

Downstream from the FDH, the situation is distinctly different due to the relatively small number

subscribers served from a single FDH location. This introduces a decision process that can be

described as “Fiber Engineering”.

Fiber Engineering

The Fiber Engineering concept describes the decision making process of how many fibers will

be required and how far along the street they should reach. Experience shows that while the

ultimate subscription rate over thousands of homes can be forecasted fairly accurately, over a

few blocks with 32 homes, the number may fluctuate considerably from one FDH to another. If

the operator “plays safe” and installs more than the average, there will be unused resources

which contributed to higher cost and longer construction schedules.

In the drop network, when using the duct and fiber cable design from many manufacturers,

fibers must be installed in the ducts passing along the street in preparation for providing fiber

optic network access when customers choose the new service. The phrase “fiber engineering”

describes the process to decide how many fibers to install in the ducts running along the street

and how far to take them. If past experience shows that If the subscription rate will be less than

Figure 9 Fiber Access Network with Pre-Terminated Drop Design

Page13of18

100%, the network operator will try to avoid the materials and labor costs to install fiber cables

in excess of what will be needed to provide service to the final number of subscribers that will be

in place a few years. This is the reason for not installing fibers to each premises location during

the network construction phase. It would raise costs dramatically.

Referring to the network schematic in Figure 9, we can see that there are two features of this

design. (1) The number of fibers will be less than the number of homes on the street, as

illustrated by the number of fiber occupied ducts (orange lines) compared to the number of

homes in the serving area. There are five fiber-occupied ducts allocated to the first two groups

totaling eight homes. (2) Individual fibers are not installed along the full length of the street. This

design saves the operator money and time, because fibers that will never be used are not

installed. But there is a risk that the subscription rate may be higher than expected requiring

additional cost to install more fibers to satisfy the un-planned demand.

Hexatronic Ribbonet® Fiber System

The Hexatronic Ribbonet® fiber optics system for the drop network eliminates the need for

guessing the amount of fiber to reserve for provisioning, because the fiber between the FDH

and the customer premises is installed only when a customer requests service. Ribbonet® is a

system of fibers, microducts and tools, including pre-terminated air-blown fibers with ferrules

suitable for field connectorization. These products are used to blow optical fiber from a new

subscriber’s premises to the FDH through the ducts that were installed during the network

Figure 10 – Handheld blowing tool and pre-terminated fiber spool for Ribbonet Fiber Installation.

Page14of18

construction phase. This is performed only when a new service request from a customer is

received, thereby ensuring that no drop cables are installed unless there is an actual

subscription request.

Since there is no break in the fiber at the street, this technique eliminates the fusion splice at the

drop cable and possibly additional splices upstream. The handheld blowing tool can be

operated by a single person. The process is fast, requiring only a few minutes to complete.

Using an innovative pre-termination assembly at the end of the fiber spool, a suitable connector

can be installed in the field for assembly with the ONT optical transceiver at the customer

premises and the passive splitter in the FDH. This blowing tool method is shown in Figure 10.

In Figure 11, we see the network along the street with this method. Notice that there are no

fibers from the FDH if the home has not requested service. The arrow pointing upstream shows

a fiber being installed with the arrow indicating the direction that the drop fiber is blown back to

the FDH. This completely eliminates the ‘fiber engineering’ uncertainties described above. Fiber

is only installed from the FDH when an individual customer request service.

The pre-terminated fiber spools have factory-installed ferrules at each end of the reel. The

complete optical connector housing can be installed over the ferrule quickly and effortlessly with

Figure 11 – Provisioning service for new subscribers using the Ribbonet system.

Page15of18

a simple fixture in the field. This substantially eliminates the need for fusion splicing in the field,

which lowers labor rates, driving down costs and speeding up schedules.

Eliminating fusion splices is a major cost savings. Splicing requires trained technicians with

higher labor rates and can be a difficult process during inclement weather. Although the

performance of a splice is excellent, it can be difficult to monitor the quality of the splice leading

to weak spots in the network that may fail at a later time.

A Network Construction Example

To illustrate the advantages of choosing Hexatronic fiber optic system solutions in a practical

way, this section presents a project example while describing the comprehensive level of

support provided by Hexatronic and the specific product advantages during the design,

procurement and construction phases of the project.

PHASE Discussion

ProjectPlanningandApproval.

Duringthiscriticalfirstphaseofafiberaccessproject,basedonyearsofexperienceworkingcloselywiththeircustomers,Hexatronicprovidesclosesupportforbothtechnicalandfinancialrequirementstocreateasolidplanfortheprojectthatmeetsthecustomer’sgoalsforcostcontrolbasedontheplannedservicesanddeploymentschedule.

NetworkDesignandLayout

WhenworkingwithHexatroniconthedesignandlayoutoftheirnetwork,customersenjoytheconfidenceofplanninganddesignbasedonafullyintegratedsetofsystemsolutionsproductsbasedonthemostrecentrequirementsofservicesandnetworkconstruction.TheHexatronicteamdevotessignificantresourcestocontinuouslyintroducenewproductsfornetworkswiththelowestTotalCostofOwnership(“TCO”)inthefiberaccessmarket.

ProjectCost Thefirststepinobtainingthebestpriceforthematerialsrequiredtobuildthenetworkisensuringthatthenetworkdesignuseshardwareefficiently.Thisisonlypracticalifthefibercables,ducts,andaccessoriesareintelligentlydesignedtoworktogetherbyasinglesupplier.TheHexatronicsystemsolutionproductsallfittogetherlikepiecesinapuzzle,whichensuresthatthefinallistofmaterialswillbesurprisinglyshortandcosteffective.

ConstructionPhase HexatronicoffersacomprehensiveAirBlownFibertrainingandcertificationforinstallers,ensuringthattheyemploythebestpracticesforinstalling,inspectingandtestingthenetworkduringandatthecloseofconstruction.Networksbuiltbycertifiedinstallersareguaranteedfor20yearsagainstfunctionalfailure.

Page16of18

DeliveryofMaterials BecausetheHexatronicsystemssolutionsproductsaremanufacturedbyasinglesupplier,thetimelydeliveryofmaterialsforaprojectcanbemanagedeffectively,avoidingdelaysandconfusioncausedbypoorcoordination.

Installationofductsandcabinetsthroughoutthenetwork.

Theinstallationofthenetworkductsproceedsquicklyandefficiently,facilitatedbythenumerouschoiceofmulti-ductdesignsanddimensions.Thechoiceofductjointsandotheraccessoriesalsocontributestotheefficientanderror-freecompletionofthisphaseoftheproject.

Blowingfibercablesintofeederanddistributionnetwork.

Inthefeederanddistributionportionsofthenetwork,thekeytostayingonscheduleistrouble-freejettingofthefibercablesthroughlengthysectionsofducts.TheHexatronicmicrocablesandmicroductproductsaregloballeadersinthedistancesandspeedthatcanbeachievedoverasinglesectionofduct.Anoteworthybenefitofthisthelengthyjettingdistanceisthatadditionalnetworkinfrastructureisnotrequiredtocompensatedforlimitedblowingdistances,asisoftenneededwithotherproducts.

Preparingthedropportionofthenetwork

TheonlyconstructionrequiredbetweentheFiberDistributionHubandtheintendedsubscribersisanemptyduct,consistingofamulti-ductfromtheFDHpassingthehomesintheserviceareaforasinglesplitter(seeFigure10).Thiseliminatesthecostofinstallingfiberswithwhateverfiberaccessterminationsmaybeusedinothermanufacturer’snetworkdesign.

Providingservicetosubscribers

Whenprovidingservicetoanewsubscriber,theHexatronicair-blownRibbonetfibersystemwiththehand-heldportableblowingtoolquicklyandeffortlesslyprovidescontinuousconnectionfromthesubscribertotheFDHandconnectiontothepassivesplitter.Thiscanbedonewithnofusionsplicingrequired,whichisasignificantadvantagesavingcost,timeandavoidingapotentialfailurepointinthenetwork.And,becausefibersareonlyinstalledwhenneeded,thenetworkcostisexactlybalancedwiththecustomerdemand.

Upgrades Giventhedifficultyofforecastingthedemandforservicesthepotentialforinstallingmorefiberstoasinglecustomerpremisesmustbeconsidered,especiallyinbusinessnetworks.ThisisanaturalextensionofthecapabilityoftheRibbonetsystemandcanbedonewithnofusionsplicingrequired.

Networkrepairsandmaintenance

Overthelifeofthenetwork,astrategyforrepairsandmaintenancemustbeanintegralpartofthenetworkdesign.TheHexatronicair-blownfibertechnologyfullysupportsalltypesofrepairs,relyingonthesameblowingtoolstoextracttheoriginalfiberandinstallanewreplacement.Theprocedureisfast,flexibleandreliable.

Page17of18

Summary

This White Paper has been written for newcomers to the use of fiber optics in access networks

for homes, apartments, businesses and campuses. The focus has been how the Hexatronic

Ribbonet® air blown fiber products enables the service provider to lower the cost of the most

expensive portion of the network, the construction of the Outside Plant. This is achieved through

the innovative technique of servicing new subscribers by blowing the drop fiber from the

customer premises to the Fiber Distribution Hub without the need for intermediate fusion splices

or connectors. This simple modification of the construction process makes dramatic

improvements in performance, reliability and cost while shortening construction schedules.

The commentary was built around underground networks for Fiber to the Home, but the

advantages of the Hexatronic Ribbonet products also apply in aerial installations, MDU

deployment, high rise office buildings and in large campus applications as well.

Fiber optics access networks are advancing rapidly in deployment and in technology. The

proven PON network architecture with the passive splitters and shared services is sharing the

fiber access platform with services designed with multiple wavelengths (WDM), Gigabit speeds,

and Ethernet signaling and point to point service provision.

Meanwhile, users of the Hexatronic air-blown fiber technology can be confident that their

network investment will retain its value and that the innovative tools and methods pioneered by

Hexatronic will continue to provide advantages in Total Cost of Ownership.

XCh ris WilliamsTech n ical So lu tio n s Man ag er

Page18of18

GLOSSARY

Access network Anynetworkthatconnectsindividualsubscribers,whetherinhomes,apartmentsorofficebuildings,tothelargerMetrocommunicationsnetwork.

ABF AcronymforAirBlownFiber,meaningopticalfiberthatissuitableforinstallingbymeansofablowingtoolinthedropnetworkorincustomerpremiseslocations.

Distribution Network ThenetworkbetweentheRemoteTerminalandtheFiberDistributionHub.IfthereisnoRemoteTerminal,TheDistributionNetworkconnectstheServiceOfficedirectlytotheFiberDistributionHub.

Drop Network ThenetworkthatbeginsattheFiberDistributionandconnectsdirectlytosubscribers.

Feeder Network TheportionofthefiberaccessnetworkthatconnectstheServiceOfficetoaRemoteTerminal.

Greenfield/brownfield

ThesetermsdescribewhethertheopticalnetworkisinstalledinaservicearethathasnopreviousinstallationandtheOSPisinstalledinnewtrenchesorpoles.Brownfieldmeansthatthenetworkisinstalled"ontop"ofapreviouslyexistingnetwork.

HDPE HighDensityPolyethylene–astrongflexiblematerialmadefrompetroleum,usedforpipesofmanydifferenttypes.

Metro Network Thelocaltelephonenetworkinalargeregionalmetropolitanareathatmayincludeseveralserviceofficelocations.Insomelocations,thetermmaysimplyrefertotelephonenetwork.

Outside Plant (“OSP”) Thisdescribesthenetworkofductsandcablesthatprovidesaconnectionbetweenopto-electronicsystemcomponentsfoundinServiceOfficesandcustomerpremises.

PON ThisisaPassiveOpticalNetworkinwhichtherearenoactivedevicesbetweentheOLTandtheONT.

Provisioning Theprocessofinstallingthedropfibertoaspecificcustomer.

Premises Thebuildingwherethesubscriberislocated.Thiscouldbeahome,anapartmentbuildingoranofficebuilding.

Service Office Atermtodescribewheretheinter-connectionbetweentheAccessnetworkandtheMetronetworkismade.ThiscouldbeatelephonecentralofficeoraCATVheadend.