Powerpoints Fiber

Question 1

What’s the preferred media for long haul transmission?

Answer 1

Fiber

Question 2

OSP (Outside plant fiber):

Answer 2

Designed to go outdoors - burial, aerial, submarine. Ruggedized for the environment.
singlemode-

Question 3

Premises Fiber:

Answer 3

Shorter in length than OSP, part of the LAN. Installed where other media isn’t appropriate.

Question 4

Fiber is immune to:

Answer 4

EMI/RFI

Question 5

Signal path for fiber ranges from ___ to

Answer 5

8mm to 62.5mm

Question 6

Dirt:

Answer 6

Enemy #1 - everything must be cleaned constantly.

Question 7

Fiber construction:

Answer 7

Jacket = covering
Buffer = color coded plastic covering
Cladding = glass
Core = hollow path for the signal

Question 8

Connector:

Answer 8

Non-permanent device for interconnection. ST, SC, LC, Duplex multimode.
MTP-prefabricated cabling systems

Question 9

Types of splicing (2) and define:

Answer 9

Splices are considered permanent joints
Fusion - lowest loss and least reflectance,welding two fibers together using special machine.
Mechanical - temporary restoration for most multimode,two fibers locked together manually.

Question 10

Optical Power:

Answer 10

Absolute measurement of signal strength.

Question 11

Optical Loss:

Answer 11

Loss of power along a path, measure in dB.

Question 12

Decibal (dB):

Answer 12

Ratio of power to loss

Question 13

Scattering:

Answer 13

Loss due to signal hitting impurities in fiber.

Question 14

Tools:

Answer 14

Cleaver = used to “cut” bear fiber, uses splices (fusion/mechanical) and can lock connections (unicam and others).
Fiber stripper = strips the buffer and coatings off the fiber for terminations.
Fusion splicer = fuses two fiber ends together, making them one piece of glass.

Question 15

Anaerobic Connector Stuff (?)

Answer 15

Polishing film, polishing puck, scribe

Question 16

Visual Fault Locator:

Answer 16

visible light source(LED or flashlight) that allows visual checking of continuity and tracing for correct connections, such as duplex connector polarity

Question 17

OTDR (Optical Time Domain Reflectometer)

Answer 17

uses backscattered light to take a snapshot of fiber,measures lenght,splice loss, or fiber attenuation, as well as for fault location in fiber from only one end of the cable

Question 18

Macrobending/Microbending:

Answer 18

Macro = attenuation from bending fiber, overbending the fiber
Micro = attenuation increase caused by high frequency small radius bends along length of fiber. compression bending of fiber

Question 19

Transceivers:

Answer 19

Send and receive data. Short for TRANSmitter and reCEIVER. Electrical signal (sending) converted to “light”, sent over the fiber, and turned back into electrical signal (receiving).

Question 20

Signal Sources (signal generators):

Answer 20

LED - cheap, low power used in LAN’s with MM fiber.
Lazers - $$ varies with type and power. VCSEL is the cheapest with the lowest power, FP - middle; DFB is the most expensive and powerful used for long haul.

Question 21

Repeaters:

Answer 21

Boost the signals

Question 22

Signal Detectors:

Answer 22

Detect optical signal and turns it back into an electrical one. Have a minimum signal level they can detect, and if the signal below that level in a run, a repeater must be used.

Question 23

Multimode:

Answer 23

Multiple signals (modes are signals).
uses step or graded index
OM3 uses lazers

Question 24

Graded/Step Index

Answer 24

Graded - has many cores within the core

Step - single boundary for reflection (single mode)

Question 25

Single Mode:

Answer 25

Supports only one mode with a smaller core and longer runs than a multimode, and almost always uses step index.
lower loss and and virtually infinate bandwith

Question 26

Types of Attentuation:

Answer 26

Absorption: Loss from signal being converted to heat.

Scattering - Loss from signal hitting molecules wrong, then redirected.

Question 27

Model Dispersion:

Answer 27

Effects only multimode - modes travel at different speeds thru the media.

Question 28

Chromatic Dispersion:

Answer 28

Effects multimode and single mode and caused by widening of the signal. If it widens too much, detector may not be able to detect the number of pulses.

big problem with LED sources in multimode

Question 29

Classify the three types of fiber:

Answer 29

Media type (single/multimode)
Cable construction
Where it's designed to be installed.

Question 30

Cable construction:

Answer 30

Tight buffered, loose tube and ribbon
125mm diameter / 250mm protective coating.
Tight buffered - 8 - 62.5mm core, 125mm cladding, 250mm coating; 900mm buffer. All together makes one tight buffered strand.
Loose Tube - 8 - 62.5mm core, 125mm cladding, 250mm coating. Multiple strands packed into each tube and may be many tubes in the cable.
Ribbon - 8 - 62.5mm core, 125mm cladding, 250mm coating;2-12 strands packed together in a ribbon, many ribbons in a cable. Very high density in a single cable.

Question 31

NEC Article 770:

Answer 31

NEC is only concerned with fire and electrical hazards.
OFN is non-conductive - - no conductive material in the cable.
OFC is conductive; cable may become energized is a fault condition.
Cable must be suitable for the environment.

Question 32

Connectors vs. splice:

Answer 32

Connectors are used when changes are often made, panels where equipment changes, and the fiber run itself is occasionally altered.
Splices are used when no changes are expected, to extend a fiber run, and repair a damaged fiber run.

Question 33

Hybrid

Composite

Answer 33

H-contains 2 types of fiber

C-contains fiber and electrical conductors

Question 34

pulling tensions

Answer 34

under tension during pulling 20x the diameter of cable

not under tension minimum long term bend 10x diameter of cable

Question 35

Reflectance

fresnel reflection,optical,return loss, or backrelection

Answer 35

amount of light that is relected back up the fiber toward source light in the connector, primary problem in connectors

Question 36

Ferel

Answer 36

white tip at end of connector

Question 37

3 methods for terminating connectors

Answer 37

glue and finish-uses anaerobics and hotglue
cam lock-unicam and others
fusion splice to pigtail