Name: 

This is The FOA Online Design Self-Study Program Case Study No. 10.It may also be used for a design lab in a CFOS/L course.

This exercise covers the design of an Optical LAN (OLAN) premises network

A large organization has decided to install an optical LAN using POL (passive optical LAN) architecture because of its cost and power savings. POL OLANs use technology similar to FTTH PONs (passive optical networks) in MDUs (multi-dwelling units). A typical link is shown below. Use common OLAN/ FTTH PON design parameters to design this system.

Premises OLAN POL:



Basic System Information:

Segments	Length	Details
OLT to PON Splitter	50-500m	Multi-fiber SM cable, SC-APC connectors
PON Splitter to ONT switch	125 - 1500 m	SC-APC connector at POL splitter, patch panel at each floor
ONT Switch		SC-APC connector
PON Splitter		32 port

GPON System	Transmitter Wavelength	Operating Loss Range
Downstream Digital	1490 nm	13-28 dB
Upstream Digital	1310 nm	13-28 dB

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

Which one of the following fibers is the best choice for this OLAN network?

The multi-fiber cable for the backbone from the PON splitter to the patch panel at each floor will be placed in plenum-rated innerduct. The cable design best for that section of the link is a ______ design and the cable must be _____.

The cable chosen for the section to the OLT 4-port switch only needs to be _____ .

Short SM cable runs typical of OLANs makes it important to use ____ connector styles to prevent ______.

How many fibers are required to connect each switch at the user work area?

In order to calculate a link power budget 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?

Typical Specifications
Provided for use as case studies for design labs in FOA courses.

Component Specifications
Fiber Loss
Singlemode at 1310 nm	TIA 568: 1 dB/km (premises), (0.4 OSP)
Singlemode at 1490/1550 nm	TIA 568: 1 dB/km (premises) (0.25 OSP)
Splice Loss	TIA 568: 0.3 dB, all types
Singlemode, fusion	0.05 dB
Singlemode, mechanical	0.3 dB
Connector Loss	TIA 568: 0.75 dB, all types
Singlemode, prepolish/ mechanical splice	0.5 dB
Singlemode, fusion splice-on (SOCs)	0.3 dB (also use for fusion spliced pigtails)
POL Splitter	Typical Loss (not including connectors on spitters)
2	4 dB
4	7dB
8	11 dB
16	15 dB
32	19 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.

Calculate the cable plant loss budget for this link. The links will use 32 port splitters. Connectors are field installed prepoished/splice connectors. Use the infomation in the "Typical Specifications" narrative above.

Here is the cable layout for calculating the loss budget:

(OLT) CC---25m---CC--SPLITTER--CC--------125m----CC(PATCH PANEL)----50m-----CC (ONT)

CC=connection
--- = fiber

The total loss should be _____ .

Calculate the cable plant loss budget for this link if instead of prepoished/splice connectors it used fusion-spliced pigtails. The links will use 32 port splitters. Use the infomation in the "Typical Specifications" narrative above.

Here is the cable layout for calculating the loss budget:

(OLT) CC---25m---CC--SPLITTER--CC--------125m----CC(PATCH PANEL)----50m-----CC (ONT)

CC=connection
--- = fiber

The total loss should be _____ (the exact number is one of the answers)

A similar OLAN system using GPON is being installed in a college campus. The OLT will be in a central facility and a  fiber will run to each building where the splitter will be installed (there may be multiple splitters in a building depending on the number of users.)
Calculate the cable plant loss budget for this link if instead of prepoished/splice connectors it used fusion-spliced pigtails. The links will use 32 port splitters. Use the infomation in the "Typical Specifications" narrative above.

Here is the cable layout for calculating the loss budget:

(OLT) CC---200-800m---CC--SPLITTER--CC--------25-125m----CC(PATCH PANEL)----50m-----CC (ONT)

CC=connection
--- = fiber

Calculate the minimum and maximum loss on a link using the range of distances shown. Use the premises cabling conservative 1dB/km atttenuation coefficient for the fiber. Round off to the nearest 0.01dB

The total loss should be _____ to ________ (the exact number is one of the answers)

For the GPON equipment listed above, will the systems operate on the planned cable plant?

The customer has a remote location that is also being considered to be added to this network. Considering the loss budget above, approximately how far away could a remote locatio be and still use the same network equipment? (Use the OSP fiber loss: 0.4 dB/km)

What parameters should be tested and documented on this GPON system cable plant to confirm proper installation and compare the loss to the calculated loss budget?

What should be included in the design documents to have the customer prepare for restoration in case of an outage?

Cables for OLANs should bend insensitive SM fiber because ___________.

OLANs based on PONs can place the PON spliters in any location along the cable plant and even cascade splitters, e.g. a 4 port splitter near the OLT and an 8 port splitter near users. The major reason to do this is a design that places splitters close to users or a cascade design __________.  (2 correct answers)

Based on the classroom curriculum and the case studies for POLs using GPON above, which of the following conculsions are correct?