Name: 
 

Fiber Optic Design Case Study 1



Completion
Complete each statement.
 

 1. 

This is The FOA Online Design Self-Study Program Case Study No. 1.

This exercise covers the design of a FTTH Network

A large metropolitan phone company has decided to test a FTTH network with the goal of deploying it throughout its system. A typical link is shown below. Use common FTTH PON design parameters to design this system.

Metro FTTH PON Link:

co001-1.jpg

Basic System Information:

SegmentsLengthDetails
CO/WDM to PON Coupler8 kmMultifiber SM cable, 2 intermediate splices, terminated with spliced-on pigtails on both ends
PON Splitter to Drop500 mSpliced pigtail at PON, preterminated at drop end
Drop to home100 mPreterminated cable
PON Splitter 32 port, 3 dB excess loss
   

GPON SystemTransmitter WavelengthMinimum loss in cable plantMaximum loss
Downstream Digital1490 nm13 dB
28 dB
Upstream Digital1310 nm13 dB
28 dB


Please enter your name, CFOT/Membership number and date to begin this exercise.
 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 2. 

The system will installed and  operated as a GPON system with triple play services..

What will be the wavelengths used for transmission?
a.
1310 nm
b.
1310 and 1490 nm
c.
1550 nm
d.
1310, 1490 and 1550 nm
 

 3. 

Which one of the following fibers is the best choice for this network?
a.
ITU G.652 - single-mode NDSF (non-dispersion-shifted fiber)
b.
ITU G.653 - single-mode dispersion-shifted optical fiber
c.
ITU G.654single-mode fiber which has the zero-dispersion wavelength around 1300 m wavelength
d.
ITU G.655single-mode NZ-DSF (nonzero dispersion-shifted) fiber), optimized for WDM and long-distance cable runs
 

 4. 

The cable for the 8 km link from the central office (C) to the fiber distribution hub (FDH) which houses the PON splitter, will be pulled in available conduit. The cable design chosen for that section of the link is a loose-tube design because the cable must be _____.
a.
Water-blocked and armored
b.
Water-blocked and rated for high pulling tension
c.
Rated for aerial installation without a messenger
d.
UL Listed for flame retardance
 

 5. 

The cable chosen for the section to the subscriber will be aerial and therefore must be _____ .
a.
ADSS cable
b.
Figure-8 design cable
c.
Loose tube cable lashed to a messenger or existing cable
d.
Any of the above
 

 6. 

How many fibers are required to connect each home?
a.
One
b.
Two
c.
Four
d.
As many as possible
 

 7. 

In order to ensure the system will work on the cable plant being designed, it is necessary to have what information on the communication system intended for use on the cable plant?
a.
Wavelength
b.
GPON power budgets
c.
PON splitter ratio and excess loss
d.
All of the above
 
 
Typical Specifications
Provided for use as case studies for design labs in FOA courses.

Component Specifications
  
Fiber Loss 
Singlemode at 1310 nm0.4 dB/km (TIA 568: 1 dB/km)
Singlemode at 1550 nm0.25 dB/km
  
Splice Loss(TIA 568: 0.3 dB, all types)
Singlemode, fusion0.05 dB
Singlemode, mechanical0.3 dB
  
Connector Loss(TIA 568: 0.75 dB, all types)
Singlemode, spliced pigtails0.3 dB

Link margin specifications for most standardized fiber optic networks are on the FOA Tech Topics Site (http://www.thefoa.org/tech/Linkspec.htm). It should be used as a reference for designers and for the courses.
 

 8. 

Using the information supplied, the next step will be to calculate the cable plant loss budget for this link.
For this GPON network, ____.
a.
Loss downstream will be less than loss upstream
b.
Loss downstream will be more than loss upstream
c.
Loss of the coupler is more downstream because it is a splitter
d.
Loss of the coupler can be ignored
 

 9. 

Using the information supplied, calculate the cable plant loss budget for this link.
Use the infomation in the "Typical Specifications" for component specifications above.
a.
21.90 dB
b.
23.19 dB
c.
21.90 dB downstream, 23.19 dB upstream
d.
23.19 dB downstream, 21.90 dB upstream
 

 10. 

For the equipment listed above, will the system operate on this cable plant?
a.
Yes
b.
Yes, but may require an attenuator at the transmitter end
c.
Yes, bmay require an attenuator at the receiver end
d.
No, it cannot work
 

Multiple Response
Identify one or more choices that best complete the statement or answer the question.
 

 11. 

What parameters should be tested and documented on this GPON system cable plant to confirm proper installation?
 a.
Insertion Loss at any one wavelength
 b.
Insertion Loss at 2 wavelengths
 c.
Downstream OTDR traces from CO to subscriber
 d.
Upstream OTDR traces from subscriber to CO
 

 12. 

What should be included in the design documents to have the customer prepare for restoration in case of an outage?
 a.
Store complete link documentation
 b.
Save leftover cable for splicing
 c.
Save several splice closures
 d.
Post emergency contact information for techs who can do restoration.
 



 
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