connector and architecture of optical fiber ppt.ppt

optics and fiber requires connections so connectors are used in FOC to connect all fibers and its very important These fibers are tough and durable due to the presence of plastic material. The modulus of this plastic material is two orders of magnitude lower than that of silica and even a 1 mm diameter graded index plastic optical fiber can be installed in conventional fiber cable routes. The diameter of the core of these fibers is 10-20 times larger than that of glass fiber which reduces the connector losses without sacrificing coupling efficiencies. So we can use inexpensive connectors, splices and transceivers made up of plastic injection-molding technology. Graded index plastic optical fiber is in great demand in customer premises to deliver high-speed services due to its high bandwidth.Optical fiber connectors An optical fiber connector terminates the end of an optical fiber, and enables quicker connection and disconnection than splicing. The connectors mechanically couple and align the cores of fibers so light can pass. Better connectors lose very little light due to reflection or misalignment of the fibers. In all, about 100 different types of fiber optic connectors have been introduced to the market. An optical fiber connector is a flexible device that connects fiber cables requiring a quick connection and disconnection. Optical fibers terminate fiber-optic connections to fiber equipment or join two fiber connections without splicing. Hundreds of optical fiber connector types are available, but the key differentiator is defined by the mechanical coupling techniques and dimensions. Optical fiber connectors ensure stable connections, as they ensure the fiber ends are optically smooth and the end-to-end positions are properly aligned. An optical fiber connector is also known as a fiber optic connector. 1980s. Most fiber connectors are spring loaded. The main components of an optical fiber connector are a ferrule, sub-assembly body, cable, stress relief boot and connector housing. The ferrule is mostly made of hardened material like stainless steel and tungsten carbide, and it ensures the alignment during connector mating. The connector body holds the ferrule and the coupling device serves the purpose of male-female configuration The fiber types for fiber optic connectors are categorized into simplex, duplex and multiple fiber connectors. A simplex connector has one fiber terminated in the connector, whereas duplex has two fibers terminated in the connector. Multiple fiber connectors can have two or more fibers terminated in the connector. Optical fiber connectors are dissimilar to other electronic connectors in that they do not have a jack and plug design. Instead they make use of the fiber mating sleeve for connection purposes.In fiber-optic communication, a single-mode optical fiber (SMF) is an optical fiber designed to carry only a single mode of light - the transverse mode. Modes are the possible solutions of the Helmholtz equation for w

1. Fiber Optic Connectors,
Splices, and Tools
Ch 6
Fiber Optics Technician’s
Manual, 3
rd
. Ed
Jim Hayes

3. Fiber Joints
Fibers must be joined when
•You need more length than you can get
on a single roll
•Connecting distribution cable to
backbone
•Connecting to electronic source and
transmitter
•Repairing a broken cable

4. Splices v. Connectors
A permanent join is a splice
Connectors are used at patch
panels, and can be disconnected

5. Optical Loss
Intrinsic Loss
•Problems the splicer
cannot fix
Core diameter mismatch
Concentricity of fiber core
or connector ferrules
Core ellipticity
Numerical Aperture
mismatch
•Images from LANshack and
tpub.com (links Ch 6a & 6c)

6. Optical Loss
Extrinsic Loss
•Problems the person
doing the splicing can
avoid
Misalignment
Bad cleaves
Air gaps
Contamination: Dirt, dust,
oil, etc.
Reflectance

7. Measuring Reflectance
The reflected light is a fraction of the
incoming light
•If 10% of the light is reflected, that is a
reflectance of 10 dB
•If 1% of the light is reflected, 20 dB
•Reflectance is not usually a problem for
data networks, but causes ghosting in
analog cable TV transmission
•Angled connectors reduce reflectance

8. Acceptable Losses
Fiber &
Joint
Loss (max) Reflectance
(min)
SM splice 0.15 dB 50 dB
SM connector1 dB 30 dB
MM splice 0.25 dB 50 dB
MM connector0.75 dB 25 dB

9. Connectors
There are four types
•Rigid Ferrule (most
common)
•Resilient ferrule
•Grooved plate hybrids
•Expanded beam
Top image shows ferrules
from swiss-jewel.com (link
Ch 6e)
Lower image shows LC, SC,
Biconic, and the obsolete
Deutsch 1000
•From thefoa.org (link Ch 6d)

10. Rigid Ferrule Connectors
2.5 mm ferrule
ST
SC
FC
Images from thefoa.org (link Ch 6d)

11. Rigid Ferrule Connectors
1.25 mm ferrule
Small Form Factor
LC
MU
LX-5
Images from thefoa.org (link Ch 6d)

12. Obsolete Connectors
Simplex (1-fiber)
SMA
D4
Biconic
Images from thefoa.org (link Ch 6d)

13. Duplex Connectors
Old, bulky
FDDI
ESCON
Images from thefoa.org (link Ch 6d)

14. Duplex Connectors
Newer, smaller
Small Form Factor
MT-RJ
Opti-Jack
Volition
Images from thefoa.org (link Ch 6d)

15. Duplex Connectors
New, popular
Small Form Factor
Duplex LC
Images from globalsources.com (link Ch 6f)

16. Ferrule Polish
To avoid an air gap
Ferrule is polished flat, or
Rounded (PC—Physical
Contact), or
Angled (APC)
•Reduces reflectance
•Cannot be mated with the
other polish types
Image from LANshack (link Ch 6a)

17. FOCIS
Fiber Optic Connector
Intermateability Standard
•A document produced by a connector
manufacturer so others can mate to
their connector
•Connectors with the same ferrule size
can be mated with adaptors
•But 2.5 mm ferrules can not be mated
with 1.25 mm ferrules

18. Telecommunications
In telecommunications, SC
•and FC
•are being replaced by
•LC
in the USA
•MU
in other countries

19. Data
In data
communications, SC
and ST
•are being replaced by
•LC

20. Connectorizing a Cable
Epoxy-polish process (Proj. 4)
•Strip cable, strip and clean fiber
•Inject adhesive, put primer on fiber,
insert fiber
•Crimp connector, cleave protruding fiber
•Air polish, final polish
•Clean and inspect by microscope
•Test connector loss with power meter

21. Cable Type and Connectors
Epoxy-polish process requires a cable
jacket and strength member to make the
connector durable
•It works for simplex, zip, or breakout cables
•But loose-tube cables and ribbon cables
contain bare fiber, and cannot be
connectorized this way
•Distribution cables contain 900 micron
buffered fiber –can be connectorized, but the
connectors are not very strong and must be
protected by hardware such as a junction box

22. Breakout Kit
Provides
tubing that
protects the
bare fiber so it
can be
terminated
•Picture from
fonetworks.com
(link Ch 4d)

23. Mounting Methods for Connectors
Adhesives
•Epoxy (room temperature-cure or oven-
cure)
•Quick-curing anaerobic adhesives (we
used this method in Proj 4)
•Hot-Melt adhesive
Crimping to hold the fiber
•Like the Unicam –see link Ch 6h
Splicing to preconnectorized pigtails
•Image of pigtail from fiberdyne.com (link Ch 6g)

24. Mounting Methods Comparison
Epoxy-Polish
•Takes longer, but costs less and has lowest
loss and reflectance
Anaerobic adhesive
•Faster than epoxy-polish but higher loss
because polishing is difficult
Crimping
•Easier, but more expensive and more loss
Splicing to preconnectorized pigtail
•Very easy, but expensive and higher loss

25. Strip, Clean and Cleave
Strip–remove 900 micron buffer (if
present) and 250 micron coating
Cleanwith alcohol and lint-free wipe
Cleave –scribe and snap; goal is a
90 degree flat break

26. End-Face Polish
Polish on a flat glass plate for a flat
finish
Polish on a rubber mat for a domed
PC finish(Physical Contact)
Angled PC finish is tilted at 8
degrees to avoid reflectance (difficult
to field-terminate)

27. Cleaning Connectors
Keep dust caps on
Use lint-free wipes and reagent-
grade isopropyl alcohol to avoid
attacking epoxy
“Canned air” has propellant, so does
compressed air from a hose

28. Splices
Splices are a permanent join of two
fibers
•Lower attenuation and reflectance than
connectors
•Stronger and cheaper than connectors
•Easier to perform than connectorization
•Mass splicing does 12 fibers at a time,
for ribbon cables

29. Mass Fusion Splicing
Video from
fitel.fiberoptic
.com (link Ch
6i)

30. Fusion Splicing
Melts the fibers together to form a
continuous fiber
Expensive machine
Strongest and best join for
singlemode fiber
•May lower bandwidth of multimode fiber
Corning videos 1-7 & 12

31. Mechanical Splicing
Mechanically aligns fibers
Contains index-matching gel to
transmit light
Equipment cost is low
Per-splice cost is high
Quality of splice varies, but better
than connectors
Fiber alignment can be tuned using a
Visual Fault Locator

32. Tools
We covered them in Project 2

43. Fiber Splices
Apermanent orsemipermanent connection
betweentwoindividualopticalfibersisknownas
fibersplice.Andtheprocessofjoiningtwo
fibersiscalledassplicing.
Typically,aspliceisusedoutsidethebuildings
andconnectorsareusedtojointhecableswithin
thebuildings.Splicesofferlowerattenuationand
lowerbackreflectionthanconnectorsandare
lessexpensive.

44. Types of Splicing
• There are two main types of
splicing
i) Fusion splicing.
ii) Mechanical splicing / V groove

45. Fusion Splicing
Fusionsplicinginvolvesbuttingtwocleanedfiberendfaces
andheatingthemuntiltheymelttogetherorfuse.
•Fusionsplicingisnormallydonewithafusionsplicerthat
controlsthealignmentofthetwofiberstokeeplossesas
lowas0.05dB.
•Fiberendsarefirstprealignedandbuttedtogetherunder
amicroscopewithmicromanipulators.Thebuttedjointis
heatedwithelectricarcorlaserpulsetomeltthefiberends
socanbebondedtogether.Fig.4.2.1showsfusionsplicing
ofopticalfibers.

46. Fusion Splicing
The splice loss depends on fiber size and eccentricity.

47. Mechanical Splicing / V
Groove
Mechanicalsplicesjointwofiberstogetherby
clampingthemwithastructureorbyepoxying
thefiberstogether.
Mechanicalsplicesmayhaveaslightlyhigherloss
andbackreflection.Thesecanbereducedby
insertingindexmatchinggel.
Vgroovemechanical splicingprovidesa
temporaryjointi.efiberscanbedisassembledif
required.Thefiberendsarebuttedtogetherina
V–shapedgrooveasshowninFig.4.2.2.

48. Mechanical Splicing / V Groove

49. Fresnel reflection
Inoptics(particularlyinfiberoptics)
alossthattakesplaceat
discontinuitiesofrefractiveindex,
especiallyatanair-glassinterface
suchasafiberendface.Atthose
interfaces,afractionoftheoptical
signalisreflectedbacktowardthe
source.Thisreflectionphenomenon
isalsocalled"Fresnelreflection
loss,"orsimply"Fresnelloss."

50. Definition of Return Loss
In technical terms, RL is the ratio of
the light reflected back from a device
under test, Pout, to the light
launched into that device, Pin,
usually expressed as a negative
number in dB.
RL = 10 log10(Pout/Pin)
Where Pout is the reflected power and
Pin is the incident, or input, power.

51. Sourcesoflossincludereflectionsand
scatteringalongthefibernetwork.
AtypicalRLvalueforanAngledPhysical
Contact(APC)connectorisabout-55dB,
whiletheRLfromanopenflatpolishtoair
istypicallyabout-14dB.
HighRLisalargeconcerninhighbitrate
digitaloranalogsinglemodesystemsand
isalsoanindicationofapotentialfailure
point,orcompromise, inanyoptical
network.