1. INTRODUCTION TO FIBRE OPTIC CABLES
FIBRE OPTICS
INTRODUCTION TO
FIBRE OPTIC CABLES

2. HOW DOES FIBRE OPTIC WORK ?
Carries Signals as Light Pulses
signals converted from electrical to light (and visa-versa) by special equipment
e.g. fibre-optic “transceiver” (transmitter / receiver)

3. FIBRE CONSTRUCTION 8, 50, 62.5 125 Cladding Glass Core Glass
The slide above shows the construction at the very heart of optical fibre, namely the “core” and the “cladding”. These two elements are both made of glass, in a manufacturing process which creates them as an inseparable unit. The core and cladding layers have slightly different optical properties, which combine to enable to the core to transmit the light pulses produced by the transmitter. The property used in this case is the “refractive index” of the glass, which is a measure of how much it can “bend” light - the same property which makes a straw appear to be bent where it enters a glass of water.
As we said earlier, the fibre itself is very small, typically only a few thousandths of an inch in diameter. The most commonly-used fibre actually has a core of 62.5 microns diameter, and a cladding of 125 microns (about 0.005”) diameter. How big is a micron? One micron - or micrometre - is 1,000 of a millimetre, or approximately ”. By comparison, an average human hair is a huge 0.004” diameter times as large !

4. PRIMARY BUFFER Primary Buffer 250 Cladding 125 Core (62.5)
As the optical fibre is so small, it needs some measure of protection so that it can be easily handled and installed. To this end, the manufacturer puts a coating called the “Primary Buffer” onto the fibre during the process of drawing the glass from a rod down into a fibre. ALL optical fibre has a Primary Buffer coating, regardless of what type of construction is ultimately used to make the cable.
The Primary Buffer is usually a polymer material, and gives some degree of physical protection to the fibre, while making it easier to handle (and easier to see !). The Primary Buffer is always 250 microns (0.25 mm, or approx ”) in diameter.
If the fibre is to be used in a cable construction known as “loose-tube”, this is the only coating applied directly to the fibre, and is normally coloured so that individual fibres in a multi-fibre bundle can be easily identified.

5. SECONDARY BUFFER Secondary Buffer 900 Primary Buffer 250 Cladding 125
Core (62.5)
For fibre which is to be used in a cable type known as “tight-jacketed”, the fibre is given a further protective coating, known as the “Secondary Buffer”. This coating is normally applied by the cable manufacturer, rather than the fibre manufacturer, and is always 900 microns (0.9 mm, or approx ”) in diameter.
The Secondary Buffer is usually a nylon type of material, which gives considerable extra strength and resilience to the fibre.
As with Primary Buffer, the Secondary Buffer coating is normally colour-coded when the fibre is to be used in a multi-fibre cable.

6. FIBRE MATERIAL Silica Glass used for high-speed data applications
Plastics
used for low-speed data / voice applications
Composite Constructions
used for low-speed and specialized applications
Although we have so far only mentioned glass as the material for the fibre itself, other materials are sometimes used, such as various types of plastics. Such materials are only used for low-speed applications, as their performance in terms of speed and distance is nowhere near that of glass. They do however have the advantage of being very cheap to produce compared with glass, and are most robust in the “bare” state.
Typical applications for plastic fibres include process-control sensors in factories, especially in industries such as petro-chemicals, where the absence of electrical connections means that the risks of hazards such as sparks are reduced to nil. Another increasing use of plastic fibre is for the interconnections between hi-fi units, especially from CD players, which are all-digital in operation.

7. FIBRE TRANSMISSION Multi-Mode graded-index
used for short / medium distance applications
step-index
early fibre type - no longer used
Single-Mode
a.k.a Mono-Mode
used for long-distance / very high-speed applications
e.g. cross-country and transatlantic communications
Although a detailed discussion of the transmission through optical fibre is beyond the scope of this course, we do need to mention that there are several different methods used.
The most common method uses what is known as “Multi-Mode” transmission, in which rays of light are propagated along the length of the fibre by being “bounced” between the sides of the core. This method is further sub-divided into two variations on the theme, namely “Step-Index”, and “Graded-Index”.
The Step-Index method was the first to be employed, but has been superseded by a more sophisticated technique called Graded-Index, in which light takes a more curved path through the core, rather than being bounced between the walls of the core in straight lines. This results in a much-improved quality of signal at the receiving end of the fibre, which in turn has allowed higher-speed signals to be transmitted over greater distances. Step-Index fibre is no longer used in the commercial environment.
Applications using the highest data rates, over the longest distances, require even higher signal quality to be maintained over the length of the fibre, and use the technique known as “Single-Mode” (or “MonoMode”) propagation. In this method, Lasers are used as the transmitters instead of LEDs, with the light beam travelling straight down the middle of the core, rather than being bounced between the core walls. As might be expected, the fibre and transceivers needed for Single-Mode operation are considerably more expensive than their Multi-Mode counterparts.

8. LIGHT TRANSMISSION MultiMode Step Index MultiMode Graded Index
The slide above illustrates the three different types of propagation within optical fibres.
SingleMode

9. COMMON FIBRE SIZES 125 µm 50 µm 62.5 µm 140 µm 100 µm 8 µm
MultiMode Graded Index
SingleMode
Unlike copper cables, which need to be produced in a very wide range of conductor sizes, fibre only needs to be made in a relatively small range of size options, and in fact just two of the four variants shown above are commonly used.
Fibre sizes are expressed by the diameters of the core and cladding, e.g. 50/125, 100/140, and so on.
The most common by far is the type designated “62.5/125”, in which the core is 62.5 microns, and cladding is 125 microns in diameter. Earlier installations used the “50/125” standard, whereas the 100/140 size was used by IBM in the early optical systems.
Because of the propagation method used in Single-Mode fibre, the core is a very much smaller diameter than for Multi-Mode. Typically, Single-Mode fibre is designated “8/125”, i.e. with core size of just 8 microns. The cladding is left as 125 microns to provide some degree of stability, and make it possible to use normal termination techniques.

10. (with Primary & Secondary Buffers)
TIGHT JACKET
Kevlar Fibres
Outer Jacket
Optical Fibre
(with Primary & Secondary Buffers)
The slide above shows the typical construction of a tight-jacketed cable. The secondary-buffered fibre is covered by a layer of “Kevlar” fibres (the same material used to make bullet-proof vests) for added strength, over which an outer jacket of a material such as PVC, PE, or LSF is laid.
For more cables needing further mechanical protection against crushing or abrasion, etc. the cable may employ further layers of armouring, similar to those used in copper cables.

11. LOOSE TUBE CONSTRUCTION
Gel filled loose tube
Optical Fibre
(with Primary Buffer)
The general construction of loose-tube fibre is shown above. As can be seen , the fibre is primary-buffered only, with the fibres being loosely contained in a rigid or semi-rigid tube. This tube may have additional embedded wire or yarn elements, which are mainly used for pulling the cable into ductwork, etc.
The illustration shows only the inner construction of the central tube element of the cable - the tube itself is further protected by optional moisture-proof tape, and / or metallic armouring, especially where the cable is intended to be buried, or used in exposed situations. For complete moisture-proofing, of underground cables, the tube itself is sometimes filled with a moisture-resistant barrier gel.
When used between buildings, loose-tube cable is normally spliced onto tight-jacketed cable in a termination box located within a few metres of the point of entry of the cable into the building.

12. FIBRE CABLE CONSTRUCTION
Tight-Buffer
fibre has primary and secondary coatings
outer jacket is drawn tight over fibre
used mainly for “indoor” applications
Loose-Tube
fibre has primary buffer only
fibres are loosely-packed in support tube
used mainly for “outdoor” applications
As mentioned earlier, there are two types of fibre cable constructions - “Tight-Jacket”, and “Loose-Tube”.
Broadly speaking, tight-jacketed fibres are used for “indoor” applications such as riser and distribution cables within a building, and for patch cords and equipment cables. They are more flexible and easier to handle than loose-tube cables, but are more expensive to produce. Tight-jacketed cable is the only type to which connectors are fitted.
Loose-tube cables are generally used for “outdoor” applications, such as links between buildings, or for cable TV distribution. Loose-tube cables are cheaper to produce, but cannot be directly-terminated in connectors, as the fibre only has a primary buffer coating, and is therefore too delicate to withstand the repeated handling stresses of being connected and disconnected.
Loose-tube cables are therefore “spliced” - i.e. directly jointed - onto other cables within protected enclosures. The fibres are generally spliced onto “pigtail” cables of tight-jacketed construction, which are then terminated with connectors to allow easy interconnection of equipment.

13. INDUSTRIAL FIBRE CABLES
NON-METALLIC FIBRE OPTIC DUCT CABLE 2-12 FIBRE
DATA SHEET SST1
OUTER SHEATH
MULTI MODE
FIBRES
ARAMID YARNS
GEL FILLED TUBE
NON-METALLIC FIBRE OPTIC DUCT CABLE FIBRE
DATA SHEET SST2
OUTER SHEATH
POLYMERIC TUBES
FILLERS
MULTIMODE
FIBRES
SST1
PE FIBRE
PE FIBRE
PE FIBRE
PE FIBRE
SST5
NY FIBRE
NY FIBRE
NY FIBRE
NY FIBRE
NY FIBRE
NY FIBRE
INTERSTICES

14. INDUSTRIAL FIBRE CABLES
NON-METALLIC FIBRE OPTIC EXTERNAL CABLE FIBRES
DATA SHEET SST5
OUTER SHEATH
INNER SHEATH
GEL FILLED TUBES
MULTIMODE
FIBRES
INTERSTICES
INDOOR/OUTDOOR INDUSTRIAL CABLE 2-12 FIBRE
DATA SHEET SST6
SST2
PE FIBRE
PE FIBRE
SST6
LS FIBRE
LS FIBRE
LS FIBRE
SHEATH
ARMOUR
MULTI MODE
FIBRES
BEDDING
ARAMID YARNS

15. INDUSTRIAL FIBRE CABLES FIRE SURVIVAL FIBRE OPTIC CABLE
DATA SHEET SST7
OUTER SHEATH
BRAID
INNER SHEATH
MICA TAPED LOOSE TUBES
STRENGTH MEMBER
SST7
LS FIBRE
LS FIBRE
LS FIBRE

16. INDUSTRIAL FIBRE CABLES
ARMOURED FIBRE OPTIC CABLE 2-24 FIBRE
OUTER SHEATH
INNER SHEATH
ARMOUR
GEL FILLED TUBES
MULTIMODE
FIBRES
DATA SHEET SST3
LEAD SHEATHED AND ARMOURED FIBRE OPTIC CABLE
2-24 FIBRE
DATA SHEET SST4
OUTER SHEATH
LEAD SHEATH
ARMOUR
MULTIMODE
FIBRES
GEL FILLED TUBES
SST3
PE FIBRE
PE FIBRE
PE FIBRE
PE FIBRE
PE FIBRE
SST4
CURRENTLY NON STOCK ITEM

17. CCTV SYSTEMS OVER OPTICAL FIBRE
INTRODUCTION & TRAINING

18. What is Closed Circuit Television?
CCTV Installations are:
Directly Linked
Non Broadcast Video Systems
VIDEO
MONITOR
CABLE

19. VIDEO + DATA + AUDIO TRANSMISSION EQUIPMENT FOR SECURITY AND SURVEILLANCE
END USER APPLICATION AREA’S
City Center Surveillance
Utilities - Water/Gas/Electricity
Traffic Surveillance
Railways - Station Complexes
London Underground Ltd
Shopping Complexes
Ministry of Defense
Airports
Public & Business Parks
Power Stations

20. What are the Basic System Components?
Camera : Black & White or Colour
Lens ( Fixed or variable Focus)
Iris ( Manual or Automatic)
Power ( DC,AC, Mains.)
Transmission
Coaxial Cable
Twisted Pair
Optical Fibre
Microwave Point to Point
Infra Red Point to Point
Monitor : Black & White or Colour
Screen Size 9” to 19”
Resolution Vertical 625 Lines (PAL)
Horizontal 750 type B/W
330 type Colour

21. OPTICAL FIBRE TRANSMISSION SYSTEM
Operating Wavelength 850nm
Multimode Fibre 50/125 or 62.5/125
Video Signal (Composite) 1Volt peak to peak
Video Only Operation Signal Fibre
Video+Data+Audio Operation Dual Fibre

22. OPTICAL FIBRE TRANSMISSION SYSTEM
Bi - Directional Data
RS 232
RS 422
RS 485
20mA Current Loop
TTL
Bi Directional Audio
Bandwidth 50Hz-20KHz
I/P Z Kohm
O/P Z <20ohm
Signal/Noise 45dB

23. PRODUCT SELECTION GUIDE
Does the system require video
only signal transfer ?
Does the system require
VIDEO+DATA+AUDIO
signal transfer ?
Does system require
VIDEO+DATA
VIDEO+AUDIO
What are the extra system
requirements ?
YES
Are there more than 3
cameras in the system ? NO
SELECT
Video Tx-2321
Video Rx-2213
15VDCP. S.-2275 NO
YES
SELECT
Video Tx-2231
Video Rx-2113 &2111
Chassis-2000
15VDCP. S.-2275
SELECT
224X Video Tx+Data Tx/Rx+Audio Tx/Rx
213X Video Rx+Data Tx/Rx+Audio Tx/Rx
” 10 Module Chassis inc Power supply
VDC Power supply
Select Data Interface required: insert identifier No at X
YES NO
SELECT
226X Video Tx+Data Tx/Rx
215X Video Rx+Data Tx/Rx
” 10 Module Chassis inc Power supply
VDC Power supply
Select Data Interface required: insert identifier No at X
YES NO
SELECT
228X Video Tx+Audio Tx/Rx
217X Video Rx+Audio Tx/Rx
” 10 Module Chassis inc Power supply
VDC Power supply
Select Data Interface required: insert identifier No at X
YES NO

24. PRODUCT RANGE 2100 Series Rackmount Plugin Modules
2200 Series Standalone Units
2300 Series Mini Modules
Video Only Facilities
2321 Video Tx Minimodule
2111 Single Channel Video Rx Rack
Channel Video Rx Rack
2211 Single Channel Rx Standalone
Channel Rx Standalone
Video + Data + Audio Facilities
2130 Video Rx + Data Tx/Rx + Audio Tx/Rx Rack
2240 Video Tx + Data Tx/ Rx + Audio Tx/Rx Standalone
Video + Data Facilities
2150 Video Rx + Data Tx/Rx Rack
2260 Video Tx + Data Tx/Rx Standalone
Video + Audio Facilities
2170 Video Rx + Audio Tx/Rx Rack
2280 Video Tx + Audio Tx/Rx Standalone

25. Market by Customer Type nd User’s rely on :-
Consultants :
Specify The System Requirements.
System Integrators :
Respond to the Specification with a “Best Solution” based on Price & Performance.
e.g.. Thorn Security Chubb Alarms Securicor Security Systems
Installers :
Serve System Integrators by providing installation services which may include the supply of cable & transmission equipment.
e.g.. Drake & Scull Eurotech Services Larkins Security Cerberus Ltd

26. SYSTEM LAYOUT VIDEO ONLY - Standalone Configuration
o o o
>
AMG
coax cable
12v DC Supply
VIDEO TX
1V p-p Composite Video
optical cable
22XX
Standalone
Receiver Rx

27. SYSTEM LAYOUT VIDEO ONLY - Rackmount System
o o o
21XX
>
AMG
System 2000
coax cable
12v DC Supply
VIDEO TX
1V p-p Composite Video
inc power supply
Optical Cable
Chassis

28. SYSTEM LAYOUT Video - Audio - Data Camera Site
Composite Video 1v p-p
PTZ Data
Audio Link
Video+Data +Audio
<
>
AMG
coax cable
12v DC Supply
opto OUT
opto IN
MIC
22XX TX
Data + Audio

29. SYSTEM LAYOUT Video - Audio - Data
Composite Video 1v p-p
Audio Link
o o o O
PTZ Data
21XX
Video+Data +Audio
<
>
AMG
System 2000
Chassis
coax cable
12v DC Supply
opto OUT
opto IN
Duplex Patchcord
+ve
-ve
MIC
22XX TX RX
Data + Audio
inc Power Supply