Report On Fiber Optic Cables: December 2015
Report On Fiber Optic Cables: December 2015
Report On Fiber Optic Cables: December 2015
net/publication/308332946
CITATIONS READS
0 17,241
4 authors, including:
Batyr Barakov
Hochschule Bremen
3 PUBLICATIONS 1 CITATION
SEE PROFILE
Some of the authors of this publication are also working on these related projects:
All content following this page was uploaded by Navaneetha C M on 20 September 2016.
Report
On
Fiber Optic Cables
1|Page
CONTENTS
1. INTRODUCTION_____________________________________ 1
4. HYBRID CABLES________________________________ 18
5. SUBMARINE CABLES_________________________________22
6. REFERENCES________________________________________28
2|Page
Fiber Optic Cables
1. Introduction
What is Fiber Optic Cable?
Cabling is the process of packaging optical fibers in a cable structure for handling and
protection. In some applications bare fibers work just fine, such as fiber optic sensors
and laboratory use. However for most communication applications fibers must be
packaged in a cable for practical use. The major benefits of fiber optic cabling are:
Easy Handling
Some communication systems require tens or even hundreds of fibers (such as a
metro backbone system). Put fibers in a cable make it very easy to install and
maintain.
Protection from damaging forces
Fiber optic cables have to be pulled into place through ducts (outdoor) or
conduits (indoor). Pulling eyes are attached to the strength members or cable
outer jackets. This is critical for isolating the fibers from the applied pulling
forces. Glass fibers cannot endure more than 0.1% to 0.2% elongation during
installation.
Protection from harsh environment factors
Cable structures protect fibers from moisture (outdoor cables), extreme
temperature (aerial cables) and influx of hydrogen into the fiber (which causes
light absorption peak at 1380nm which in turn impair fibers’ transmission
properties).
Based upon fiber types in a cable, fiber optic cables can be categorized as three types.
Hybrid/Composite Cable
Both single mode and multimode fibers are packaged in one cable, such as 4 multimode
fibers and 4 single mode fibers in a single cable.
3|Page
Elements in a Fiber Optic Cables
The construction design and choices of materials are vital in determining characteristics
of a cable. The design factors for some types of fiber optic cables are listed below.
Indoor cables
Fire safety is the number one factor in selecting indoor cables, particularly those that
run through plenum spaces. Indoor cables must pass the flame-retardant and smoke-
inhibitor ratings specified by NEC.
Outdoor cables
Moisture resistance and temperature tolerance are the major factors when choosing
materials for outdoor environment cables. They also need to be ultraviolet (UV)
resistant.
Polyethylene (PE)
PE (black color) is the standard jacket material for outdoor fiber optic cables. PE has
excellent moisture – and weather-resistance properties. It has very stable dielectric
properties over a wide temperature range. It is also abrasion-resistant.
PVC is the most common material for indoor cables; however it can also be used for
outdoor cables. It is flexible and fire-retardant. PVC is more expensive than PE.
PVDF is used for plenum cables because it has better fire-retardant properties than PE
and produces little smoke.
LSZH plastics are used for a special kind of cable called LSZH cables. They produce
little smoke and no toxic halogen compounds. But they are the most expensive jacket
material.
Aramid Yarn
Aramid yarn is a yellow color, fiber looking material. It is strong and is used to bundle
and protect the loose tubes or fibers in the cable. It is the strength member to provide
tensile strength along the length of the cable during and after installation. When a cable
is pulled into a duct, the tension is applied to the aramid yarn instead of the fibers.
4|Page
Central Strength Member
Many fiber optic cables has a central strength member, made of steel, fiberglass or
aramid yarn. Central strength members are needed to provide the rigidity to keep the
cable from buckling. Central strength members are common in outdoor cables and some
high fiber counts indoor cables.
Gel Compound
Gel compound fills buffer tubes and cable interiors, making the cable impervious to
water. It needs to be completely cleaned off when the cable end is stripped for
termination.
Ripcord
Ripcord is a thin but very strong thread embedded just below the cable jacket. Its role is
to split the cable easily without harming cable interiors.
Fiber optic cable are available in a wide variety of physical constructions. Fiber cables
can be anything from simple simplex or duplex (zipcord) cables used for jumpers to
144-fiber cable for intercity transmission.
However most of the fibers used in these cables come down to two basic configurations
– 900µm tight buffered fibers or 250 µm coated fibers (also called bare fibers). Actually
tight buffered fibers cover a coated fiber(the coating is soft plastic) with a thick layer of
harder plastic, making it easier to handle and providing physical protection.
5|Page
The structure of a 250µm coated fiber (bare fiber)
Core (9µm for standard single mode fibers, 50µm or 62.5µm for multimode
fibers)
Cladding (125µm)
Coating (soft plastic, 250µm is the most popular, sometimes 400µm is also used)
Core (9µm for standard single mode fibers, 50µm or 62.5µm for multimode
fibers)
Cladding (125µm)
Coating (soft plastic, 250µm)
Tight buffer (hard plastic, 900µm)
Based on 900µm tight buffered fiber and 250µm coated fiber there are two basic types
of fiber optic cable constructions – Tight Buffered Cable and Loose Tube Cable.
Multiple color coded 900um tight buffered fibers can be packed tightly together in a
compact cable structure, an approach widely used indoors, these cables are called tight
buffered cables. Tight buffered cables are used to connect outside plant cables to
terminal equipment, and also for linking various devices in a premises network.
Multi-fiber, tight buffered cables often are used for intra-building, risers, general
building and plenum applications. Tight buffered cables are mostly built for indoor
6|Page
applications, although some tight buffered cables have been built for outdoor
applications too.
On the other hand multiple (up to 12) 250µm coated fibers (bare fibers) can be
put inside a color coded, flexible plastic tube, which usually is filled with a gel
compound that prevents moisture from seeping through the hollow tube. Buffer tubes
are stranded around a dielectric or steel central member. Aramid yarn are used as
primary strength member. Then an outer polyethylene jacket is extruded over the core.
These cables are called loose tube cables.
7|Page
Loose tube structure isolates the fibers from the cable structure. This is a big advantage
in handling thermal and other stresses encountered outdoors, which is why most loose
tube fiber optic cables are built for outdoor applications.
Loose-tube cables typically are used for outside-plant installation in aerial, duct and
direct-buried applications.
8|Page
Figure 1.6: Cross Section of a Loose Tube Fiber Optic Cable
2. Categories of Cabling
1. Indoor Cables
2. Outdoor Cables
3. Indoor/Outdoor
They can consist of one (simplex), two (duplex) or more (multifiber) individual fibers.
Simplex cables provide one-way transmission, while duplex cables allow transmission
in both direction. Multifiber cables may carry many fiber pairs surrounding a central
strength member, as shown in the Figure: 2-1; or they may take the form of ribbon
cables, which are individual cables in a row surrounded by a single jacket Figure: 2-2
9|Page
Indoor Cables
Elaborating the indoor optical cables they have a diverse variety of applications inside a
building. They are replacing outdoor cables because the indoor cables have more
flexibility, cheaper and convenience to use inside a building. Indoor cables have some
characteristics that allow it to be more favorable. Such as:
No need grounding and lightning protection - Since they are free of metal
Easy to strip - They are 900µm TBII tight buffered fibers
All information of the cable can be printed on the outer sheath.
Simplex Round Indoor Cable Duplex Zipcord Indoor Cable Multi-fiber Distribution Indoor Cable
10 | P a g e
Codes
Table 1.1 2
11 | P a g e
Color Coding
It would seems that the color coding, the color of the jackets and buffers means the
characteristics (Fire retardant, Mechanical, Single or Multi mode, Dielectric properties
of the sheath…) of the cable. But not all manufacturers adhere to the same standards.
The color coding, the difference of the color is used to identify the cables, to visual
recognize each of them to connect in right order. Table: 1.1 shows the difference of
used colors for cables 1-12 fiber strands. In case of more fibers they are indicated with
same colors, but with lines or dotted lines.
General requirements
Cables must not be supportive and flame retardant and have low smoke and
halogen;
12 | P a g e
Interconnect Cables
Interconnect cables are used to connect the devices, the blocks in the device, process
controls, wired office systems to transmit data, image, video, and voice in intra-building
distribution. They can one or two fiber designed (Simplex Round, Duplex Zipcord,
Duplex Round).
Figure: 2-5
These cables suffer almost minimal mechanical loading. For compounds of the blocks
in the device is often sufficient optical fibers in buffer coating. If there is frequently
switching of interconnect cables for connections, it may contain coils of protective
aramid yarns and an additional outer shell, which provides increased mechanical
strength.
Duplex Zipcord
Zipcord Fiber Optic Cables structure contains two simplex cables jointed together; it
can be easily split apart by hands. It is used for general indoor applications. Zipcord
fiber optic cable can be manufactured as single mode or multimode and with various
kinds of connectors like LC, SC, ST. Usually on the zipcord cable, each side is two
connectors, and the two connectors may be joined together by a clip. The buffers are
color coded for easy identification and installation. This fiber cable is perfect for data
centers and indoor point to point connections.
13 | P a g e
Advantages
Standard fiber count : 2C
Light weight and flexible
Ideal for tight radius installation
Easy termination, rugged cable-connector interface
The simplex cords can be easily separated from each other
Application
For use in the cable assemblies including
For patch panels within communication closet
For communication closet jumper assemblies
Suitable for dropped ceiling installation
Figure – 3.1
Figure 2.7: **OLT-Optical Line Termination; ONU-Optical Network Unit**
Construction
Figure – 2.8
① Optical fiber type : SMF(Sing Mode optical Fiber), MMF (Multi Mode optical
Fiber)
② Tight Buffer Coating : PVC or LSZH (Low Smoke Zero Halogen)
③ Dielectric Strength Member : Aramid yarn
④ Jacket : PVC or LSZH (Low Smoke Zero Halogen)
14 | P a g e
3. Multifiber Breakout Cable
Multifiber Breakout Cable is a favorite where rugged cables are desirable or direct
termination without junction boxes, patch panels or other hardware is needed. They are
made of several simplex cables bundled together inside a common jacket. This is a
strong, rugged design, but is larger and more expensive than the distribution cables. It is
suitable for conduit runs, riser and plenum applications. It's perfect for industrial
applications where ruggedness is needed. Because each fiber is individually reinforced,
this design allows for quick termination to connectors and does not require patch panels
or boxes. Breakout cable can be more economic where fiber count isn't too large and
distances too long, because is requires so much less labour to terminate. A breakout
cable is used when you need to connect two areas of your infrastructure together;
whether this is connecting floors in the same building, connecting two buildings on your
campus or for linking deployable equipment to a control room.
Cable Design
The design of breakout-style cable adds strength for ruggedized drops, however the
cable is larger and more expensive than distribution-style cable.
Since each fiber is individually reinforced, the cable can be easily divided into
individual fiber lines. Each simplex cable within the outer jacket may be broken out and
then continue as a patch cable, for example in a fiber to the desk application in an office
building. This enables connector termination without requiring special junctions, and
can reduce or eliminate the need for fiber optic patch panels or an optical distribution
frame. Breakout cable requires terminations to be done with simple connectors, which
may be preferred for some situations. A more common solution today is the use of a
fan-out kit that adds a jacket to the very fine strands of other cable types. . Breakout
Cable is by far the least expensive and easiest cable type to terminate and requires the
least experience on the part of the installer.
15 | P a g e
Break Out Cable Varieties
Outdoor breakout cables have riser and plenum rated versions. These cables are
flexible, easy to handle and simple to install. Since they do not use gel, the connectors
can be terminated directly onto the 900µm fiber without difficult-to-use kits. This
provides an easy and overall less expensive installation.
16 | P a g e
Temperature specifications:
Application
1. Ideal for installations requiring an extremely rugged and reliable cable design
where maximum mechanical and environmental protection are necessary
Plenum is an air-handling, air flowing and air distribution system space which is found
above drop ceiling tiles or heating and ventilation ducts. The outer jacket of plenum
rated cables are made of materials that retard the spread of flame, produce little smoke
and protect electronic equipment from damage in fires. Plenum cables can be run
through plenum spaces without special conduits. Plenum rated cables are more
expensive, because of the jacket material.
Temperature:
17 | P a g e
Advantages:
Riser is a pathway such as floor opening, shaft or duct that runs vertically through
floors. Riser rated cables can be run through building vertical shafts (risers) or from one
floor to another floor.
OFNR cables can not be installed in plenum areas since they do not have the required
fire and smoking rating as Plenum rated cables. OFNP plenum cables can be used as
substitutes for OFNR cables.
CROSS SECTION:
18 | P a g e
Temperature
• Operating temperature, range -20 .. 75°C
• Ambient installation temperature, range -20 .. 75°C
• Storage temperature, range -40 .. 85°C
Advantages
One cable design meeting all structured cabling network communications applications
High tensile strength provides for greater pulling distances
Ease of installation
Broad design selection allows for mix and match of fiber components to specific
networking applications
Low cable plant maintenance
Armor option adds crush resistance and protection from rodent attacks
Maintenance
19 | P a g e
4. Hybrid Cables
What is Hybrid Cable?
Hybrid cables are ideal for networks involving real-time image transport or
sharing large files. Such applications include computer-aided design and manufacturing,
laboratory simulators and hospital imaging systems--or, any other application that may
require even higher bandwidths in the future.
Copper cables are inexpensive and installation is easier. If we send data over copper
cable, every 30Kms we need repeaters to avoid power drop. Whereas optical fibers have
lower transmission losses compared to copper wires. This means that data can be sent
over long distances, thereby reducing the number of intermediate repeaters needed for
these spans.
In a typical HFC cable scenario, a service provider stretches a fiber optic backbone that
is located in close proximity to a customer/end-user and terminates it at a node device.
20 | P a g e
From the node device, the fiber's transmitted light signals are converted into radio
frequency signals, which are transmitted via coaxial cable, which expands until it
reaches the end user or device.
Structure of the hybrid cable
Hybrid fiber cable/coax cable consists of a single cable sheath that contains fibers and
copper cables in different combination. The hybrid cable can have both the distribution
as well as the breakout structure. For instance, cables for HDTV cameras usually base
on the distribution structure that provides high flexibility with small diameter and low
weight. The cable used for underground mining applications will use the breakout
structure for better protection against mechanical tensions and working forces.
Figure 4.2: HDTV camera hybrid cable. Figure 4.3: Industrial hybrid cable, breakout structure
(Visible optical fibers (yellow and blue), screen braid
and electrical wires (red, green and black) and fillers (white))
Figure 4.4: Cross-section of the hybrid cable Figure 4.5: Cross-section of the breakout type hybrid
cable
The combination of the diameters and gauges of the copper wires or types of the optical
fibers is virtually unlimited and depends entirely on the customer needs and
requirements. The copper wires can be employed to carry electrical signals or supply
the power, so there could be a whole variety of copper cables like wires, twisted pairs,
coax, triax, etc. This cable functions for CCTV in tunnels, buildings and airports.
21 | P a g e
Applications:
HFC cable has a bright future for WAN communications as more is installed in cable
TV infrastructure. Using HFC, cable operators can provide telephone service, multiple
channels of interactive TV and high-speed data services for PC’s. A full HFC system
can deliver:
1. Plain old telephone services
2. Over 200 digital TV channels
3. Over 400 digital point channels (customer-requested services)
High-speed, two-way digital data link for PCs.
For example, a cable Internet Service Provider (ISP) may use fiber optic from the
central office to each branch exchange of a town. The Internet is delivered on coaxial
cables from there to the customer’s home or office. This combination of fiber and
coaxial cable allows higher speeds to be reached through a fiber backbone close to the
customer, while remaining economical and compatible via coaxial cable-based delivery
to end users/consumers.
In a hybrid fiber-coaxial cable system, the television channels are sent from the
cable system's distribution facility, the hub, to local communities through optical
fiber trunk lines. At the local community, a box called an optical node translates the
signal from a light beam to electrical signal, and sends it over coaxial cable lines for
distribution to subscriber residences. The fiber optic trunk lines provide adequate
bandwidth to allow future expansion and new bandwidth-intensive services.
Advantages
Cost – Less maintenance costs due to fewer amplifiers required and less
electricity is consumed.
22 | P a g e
Reliability – Reliable, immune to noise and almost non-existent attenuation
(distortion).
Bandwidth – High bandwidth capabilities, increased from traditional CaTV
network (up to 330MHz or 450MHz) to 750MHz with HFC.
Flexibility – Has ability to adapt to new services such as voice, data or video
without changing existing operational parameters (TE Consulting)
Size – Lighter weight and thinner than copper cables with the same bandwidth,
much less space is required in underground cabling ducts and easier for
installation engineers to handle.
Security – Much more difficult to tap information, a great advantage for banks
and security installations. Immune to Electromagnetic interference from radio
signals, car ignition systems, lightning etc. Can be routed safely through
explosive or flammable atmospheres.
Technology Support – Can support Cable telephones, increased number of
CaTV channels (to over 200), a direct infrastructure to new Digital TV standards
which assume that networks will use HFC backbones and ATM services.
Availability – No need to dial-up or tie up a phone line as it uses a separate
connection, Cable Internet has constant connectivity.
Disadvantages
Cost – More expensive than Coaxial Cable, especially costly to rural subscribers
due to long cables required.
Reliability – Due to the huge number of users that a fiber will support, a train
derailment, earthquake or other traumatic even can have catastrophic
proportions.
Skill Required – Optical fibers cannot be joined (spliced) together as easily as
copper cable and requires additional training of personnel and expensive
precision splicing and measurement equipment.
Symmetry – Asymmetrical, not based on new interactive multimedia. The
upstream paths in the HFC network are slower than downstream.
Signal Quality – Is reduced as more subscribers use the network. Speed of
transmissions also decreases. HFC network speeds are limited by the number of
users using the network at the same time. Even though a single 7MHz channel
can have theoretical speeds of 30Mbps, much of this speed is shared between all
the users on the neighborhood node using a cable modem at the same time. Each
node is capable of supporting services to 500 - 2000 homes.
Future Prospects:
23 | P a g e
5. Submarine Cables
What is a submarine cable?
A submarine communications cable is a cable laid on the sea bed between land-
based stations to carry telecommunication signals across stretches of ocean. The first
submarine communications cable was laid in the 1850s and carried telegraphy traffic.
Subsequent generations of cables carried telephone traffic, then data
communications traffic. Modern cables use optical fiber technology to carry digital
data, which includes telephone, Internet and private data traffic.
As of 2010, submarine cables link all the world's continents except Antarctica.
Satellites have a two-fold problem: latency and bit loss. Sending and receiving
signals to and from space takes time. Meanwhile, researchers have developed optical
fibers that can transmit information at 99.7% the speed of light.
The first trans-Atlantic cables were laid in the 1860s, and trans-Pacific cables
followed in the early 1900s. These cables were incredibly low-bandwidth because
repeaters didn’t exist then, so the only way of getting a signal across was by upping the
voltage and creating a very noisy link. By the early 1900s, the British Empire had
already connected up most of the continents (see image below).
24 | P a g e
Figure 5.1: Continents connected by British Empire by early 1900s.
Construction:
Modern cables are typically about 25 millimeters (0.98 in) in diameter and weigh
around 1.4 kilograms per meter (0.4 lb/ft) for the deep-sea sections which comprise the
majority of the run, although larger and heavier cables are used for shallow-water
sections near shore. The diameter of a shallow water cable is about the same as a soda
can, while deep water cables are much thinner—about the size of a Marker. As seen
in Figure below, it has a range of protections; double armored, single armored,
lightweight protected, and lightweight. These protections will keep the optical fibers
safe at a depth of 8000 m in various seabed conditions.
25 | P a g e
The submarine fiber optic cable contains the same components as a land cable, except it
has more protection.
A cross section of the shore-end of a modern submarine communications cable.
1 – Polyethylene
2 – Mylar tape
3 – Stranded steel wires
4 – Aluminum water barrier
5 – Polycarbonate
6 – Copper or aluminum tube
7 – Petroleum jelly
8 – Optical fibers
As far as laying a submarine cable, specialized cable-laying ships must be used called
cable-layers. When a cable is broken (usually by a trawler, volcano, tectonic activities,
shark bites ) another special ship must be used for repair. This generally means that
laying a cable is logistically challenging and very expensive. The cables must generally
be run across flat surfaces of the ocean floor, and care is taken to avoid coral reefs,
sunken ships, fish beds, and other ecological habitats and general obstructions.
26 | P a g e
Figure 5.4.: Laying of Submarine cable
Bandwidth problems:
Modern optical fiber repeaters use a solid-state optical amplifier, usually an Erbium-
doped fiber amplifier. Each repeater contains separate equipment for each fiber. These
comprise signal reforming, error measurement and controls. A solid-state laser
dispatches the signal into the next length of fiber. The solid-state laser excites a short
length of doped fiber that itself acts as a laser amplifier. As the light passes through the
fiber, it is amplified. This system also permits wavelength-division multiplexing, which
dramatically increases the capacity of the fiber.
27 | P a g e
Figure 5.5.: Diagram of an optical submarine cable repeater.
Repeaters are powered by a constant direct current passed down the conductor near the
center of the cable, so all repeaters in a cable are in series. Power feed equipment is
installed at the terminal stations. Typically both ends share the current generation with
one end providing a positive voltage and the other a negative voltage. A virtual
earth point exists roughly halfway along the cable under normal operation. The
amplifiers or repeaters derive their power from the potential difference across them.
28 | P a g e
Importance of submarine cables:
The reliability of submarine cables is high, especially when (as noted above) multiple
paths are available in the event of a cable break. Also, the total carrying capacity of
submarine cables is in the terabits per second, while satellites typically offer only
1000 megabits per second and display higher latency.
Future Prospects:
As of 2014, there are 285 communications cables at the bottom of the ocean, and 22
of them are not yet in use. These are called ―dark cables.‖ Submarine cables have a life
expectancy of 25 years, during which time they are considered economically viable
from a capacity standpoint. Over the last decade, however, global data consumption has
exploded. In 2013, Internet traffic was 5 gigabytes per capita; this number is expected to
reach 14 gigabytes per capita by 2018. Such an increase would obviously pose a
capacity problem and require more frequent cable upgrades. However, new techniques
in phase modulation and improvements in submarine line terminal equipment (SLTE)
have boosted capacity in some places by as much as 8000%. The wires we have are
more than ready for the traffic to come.
29 | P a g e
6. References:
30 | P a g e