Fiber Optics Network Design

Part 2. Purpose of this book is to provide a reference guide to those involved with the design of fiber optic networks or those teaching the personnel who will do this work.

Fiber optic network designer must have knowledge of electrical power systems and hardware as well as communications design.

True

The first consideration for any network is choosing the proper fiber optic cable type.

False

Fiber optic network designer should have an in-depth knowledge of

All the above

The first requirement that must be considered for a new fiber optic project is

The customer's communicatons system requirements

Optical fibers can transmit either voice, data or video and either analog or digital signals.

True

Singlemode fiber has a smaller core than multimode fiber.

False

In an optical fiber, the light is transmitted through the…

Core

The diameter of an optical fiber is traditionally measured in…

Micrometers

Loss of a fiber or any fiber in a cable is measured in….

dB

10 dB corresponds to a factor of __________ in power.

10

A fiber stripper removes the ____ of the fiber.

Buffer coating

The _______ protects the fiber from harm.

All of the above

The wavelength of light used for most fiber optic systems is in the _______ region and is ________ to the human eye.

infrared, invisible

Any standard’s main goal is to create uniform specifications for products that ensure interoperability among various manufacturer’s products.

True

Customers purchasing products generally do not need to depend on understanding the meaning of the standards themselves.

False

Besides cabling, Ethernet and WiFi are examples of industry standards.

True

Once written, standards never change

False

The goal of the TIA TR-42 committee is to produce a ________ for cabling that manufacturers can use for developing communications products.

standard nomenclature, predictable minimum performance level, application, test specifications

The biggest advantage of optical fiber is the fact it is the most cost effective means of transporting information.

True

Telephone networks have been converted to fiber, including long distance and metropolitan networks, but fiber to the home (FTTH) is not yet feasible.

False

Today, with the exception of some _________, the entire telephone backbone is fiber optics.

Rugged or remote locations

_______ companies overbuild with fiber, often lashing fiber optic cables to installed aerial coax cable.

CATV

Copper networks can be converted to fiber optics using ________

Media converters

The bandwidth and distance capability of optical fiber means that _______

Fewer cables and repeaters needed. Less power is consumed and less maintenance is required.

Which of the following communications systems typically use fiber optic backbones?

Telephones, CATV, Internet, Cell Phones

Outside plant cabling can be installed by ______

All of the above

Underground cable generally includes a gel for protection from __________

Moisture

Armored cable is used in outside plant installations to ________

Prevent rodent damage

Most outside plant installations are singlemode fiber.

True

Concatenation or the joining of two cables in a long outside plant run is almost always done by ________

Fusion splicing

Premise cables in LAN backbones often contain ____

Both MM & SM fiber

Premises cables must be rated for ______ to meet codes.

Fire retardance

Underground cable refers to a cable that is __________

Pulled in underground conduit or ducts

Direct buried cable refers to a cable that is __________

Buried in a trench

Cable should be buried at a depth ________

Required by local building codes

Microtrenching refers to cables __________

Buried in grooves sawed in roadways

Direct buried cables generally have armor to prevent rodent damage and __________

Prevent damage from the material used to fill the trench

Splices for underground cables can be ____________

Any or all of the above

The most common cause of failure of underground cable is ____________

“Backhoe fade” AKA Back”Sage” fade

When installing direct-buried or underground cables, the first thing you should do is ________________________

Call 811 or call811.com

The biggest issue with aerial cable design is to ensure the cable is able to withstand the _______ over the long term

Wind

TIA 568 standards for premises or structured cabling including network architectures and cable lengths were derived from ______

Intense industry debates

TIA 568 limits unshielded twisted pair (UTP) cables to ______ length, including a maximum of _____ of flexible patchcords.

100, 10

The connector used for all UTP cables is often called an RJ-45 but is technically a modular 8-pin connector

True

Category-rated UTP cables are specified by performance to allow ________

Choosing a proper cable for the speed of the network

Fiber optic cable is often used in premises cabling for network backbones because ________

All of the above

You should not mix UTP and fiber optic cable in the same cable tray because _______

The copper cable is much heavier and can crush the fiber optic cable

Cabling in a communications project _____

All of the above

Cabling may only be a few percent of the cost of a communications system but causes most of the problems.

True

The first thing to consider when planning a cabling project is ______

The needs of the communications system(s) using the cabling

Standards are written to ensure that cabling _________

Performs adequately for the systems using it

Codes are written to ensure that cabling __________

Meets local laws

Codes related to cabling

All of the above

Copper, fiber or wireless?

Whichever makes sense for the communications system(s)

When choosing a contractor, the most important issue is not

Whoever makes the lowest bid

When abandoned cable is found inside a building, ________ and _______

It should be removed to meet the NEC requirements and recycled

The first thing to consider when planning an installation is _________

Safety

After defining the project, as the design begins, the first thing to create is the __________

Documentation

Documentation includes all information on the cable plant project plus marking and labeling appropriate components, with copies provided to the customer and backups arranged

True

Paperwork for a fiber optic project should be started ________

As soon as the project starts

Scope of Work (SOW)

Describes the work to be performed or the services to be provided by a contractor.

Request for Proposal (ROP)

Invitation to suppliers to join into a bidding process for specific products or services.

Request for Quote (RFQ)

Invitation for suppliers to submit a proposal on a specific.

Contract

A legal document between the contractor and the customer specifying the requirements of the project.

The routing or location of the fiber optic cable plant being designed is the primary issue which will determine the types of components chosen.

True

Direct burial cable and udnerground cable are the same

False

All cables installed indoors must meet flammability standard determined by local building codes.

True

Most OSP SM cable is spliced using _________

Fusion splicing

Most SM fiber is terminated by ____________

Fusion spliced pigtails

Most popular tight-buffered cable used in premises application is _________

Distribution

Loss budgets are used to ensure _______

All of the above

When calculating the loss budget of a cable plant, you total the losses of all the __________ in the link.

All of the above

When calculation the loss budget, you should choose the component losses using _________

Loss values from industry standards that are always worst case

You calculate the contribution of the loss of the fiber to the loss budget by ______________

Multiplying the length of the fiber by the attenuation coefficient

When calculating the contribution of the fiber loss to the loss budget, you must consider the ________

Wavelength of the fiber

A loss budget is the calculated loss of the cable plant while a power budget is the optical loss tolerable to a communications system.

True

Connector losses are calculated by adding up all the losses of the connectors, always ________________

Including the connectors on each end of the cable plant

A premises cabling link 100m long uses multimode fiber (3.0 dB/km @ 850nm) and two connections in the middle as well as two connectors on the ends (0.50 dB/connector). The calculated loss budget would be _________________

2.3dB

Recalculate the loss budget of the premises cabling link above (100m with 2 connections and connectors on each end) using TIA 568 worst case component losses (fiber at 3.5 dB/km and connections at 0.75dB). Then the loss budget now becomes _____

3.35dB

When comparing calculated loss budgets to test values of the installed cable plant in the field to determine whether an installation is acceptable, it’s important to remember ___________

All of the above

For testing a terminated fiber optic cable or a patchcord, the instrument(s) you need is (are):

FO power meter and source

The correct way to calibrate “0 dB” or no loss is with:

Any of the above as long as the method is documented

Mixing 50/125 micron fiber with 62.5/125 micron fiber can cause _________

Excess loss when coupling from Excess loss when coupling from 62.5/125 to 50/125 fiber

If testing shows high loss in a cable, the fault can often be found by:

All of the above

The biggest factor in the uncertainty of loss measurements in MM fiber is __________

The mode power distribution caused by the test source

An OTDR can be used to find bad connectors or splices in a high loss cable plant, if the OTDR has ____________

Sufficient gain

If an OTDR cannot find the problem, a _________ may solve the problem.

VFL

OTDRs can measure _____, ________ and ______

Distance, attenuation, reflection

Length measurements by the OTDR are shorter than actual cable because the fiber is longer than the cable itself

False

OTDR connector or splice loss measurements are only accurate if you _________

Use reference quality connectors

Once the design of a fiber optic project is complete and documented, the bulk of the work is done.

False

While the Project Manager is the most important person in the project, there must be a backup person so there is a contact available, often 24/7, during the project.

True

It is not necessary for the on-site supervisor to inspect and verify test results until the final stage of the project.

False

Planning a project properly includes creating a ________ before beginning the design process

Checklist

________ determines that the project was installed correctly.

Acceptance by customer

The most important thing you can have when trying to restore a fiber optic network is ______________

Documentation

During the project, it may be necessary to worth with ________ to complete the project

engineers, city/county permit authorities, persons/organizations whose property may be affected, electrical inspectors, electrical contactors, building inspectors, local licensing authorities, etc….

To do a proper restoration on a buried OSP cable, you are going to need the following equipment and supplies in addition to the documentation.

Fiber toolkit, including mechanical/fusion splicer, sufficient length of fiber, one or two splice enclosures, appropriate test equipment.