fo cable presentation
TRANSCRIPT
Core (Optical Fiber)SINGLE MODE FIBER (9/125-G 652D)
In fiber-optic communication, a single-mode optical fiber (SMF) (monomode
optical fiber, single-mode optical waveguide, or unimode fiber) is
an optical fiber designed to carry only a single ray of light (mode). Modes are the
possible solutions of the Helmholtz equation for waves, which is obtained by
combining Maxwell's equations and the boundary conditions. These modes define
the way the wave travels through space, i.e. how the wave is distributed in
space. Waves can have the same mode but have different frequencies. This is the
case in single-mode fibers, where we can have waves with different frequencies,
but of the same mode, which means that they are distributed in space in the
same way, and that gives us a single ray of light. Although the ray travels parallel
to the length of the fiber, it is often called transverse mode since
its electromagnetic vibrations occur perpendicular (transverse) to the length of
the fiber. The 2009 Nobel Prize in Physics was awarded to Charles K. Kao for his
theoretical work on the single-mode optical fiber.[1]
The core of a conventional optical fiber is a cylinder of glass or plastic that runs
along the fiber's length. The core is surrounded by a medium with a lower index
of refraction, typically a cladding of a different glass, or plastic. Light travelling in
the core reflects from the core-cladding boundary due to total internal reflection,
as long as the angle between the light and the boundary is less than the critical
angle. As a result, the fiber transmits all rays that enter the fiber with a
sufficiently small angle to the fiber's axis. The limiting angle is called
the acceptance angle, and the rays that are confined by the core/cladding
boundary are called guided rays.
The core is characterized by its diameter or cross-sectional area. In most cases
the core's cross-section should be circular, but the diameter is more rigorously
defined as the average of the diameters of the smallest circle that can be
circumscribed about the core-cladding boundary, and the largest circle that can
be inscribed within the core-cladding boundary. This allows for deviations from
circularity due to manufacturing variation.
Another commonly-quoted statistic for core size is the mode field diameter. This
is the diameter at which the intensity of light in the fiber falls to some specified
fraction of maximum (usually 1/e2≈13.5%). For single-mode fiber, the mode field
diameter is larger than the physical diameter of the core, because the light
penetrates slightly into the cladding as an evanescent wave.
Multi-Mode Fiber (OM1 - 62,5/125)
The propagation of light through a multi-mode optical fiber.
Multi-mode optical fiber (multimode fiber or MM fiber or fibre) is a type
of optical fiber mostly used for communication over short distances, such as
within a building or on a campus. Typical multimode links have data rates of 10
Mbit/s to 10 Gbit/s over link lengths of up to 600 meters—more than sufficient for
the majority of premises applications.
Applications
The equipment used for communications over multi-mode optical fiber is less
expensive than that for single-mode optical fiber.[1] Typical transmission speed
and distance limits are 100 Mbit/s for distances up to 2 km (100BASE-FX),
1 Gbit/s to 220–550 m (1000BASE-SX), and 10 Gbit/s to 300 m (10GBASE-SR).
Because of its high capacity and reliability, multi-mode optical fiber generally is
used for backbone applications in buildings. An increasing number of users are
taking the benefits of fiber closer to the user by running fiber to the desktop or to
the zone. Standards-compliant architectures such as Centralized Cabling
and fiber to the telecom enclosure offer users the ability to leverage the distance
capabilities of fiber by centralizing electronics in telecommunications rooms,
rather than having active electronics on each floor.
ETK Cable - .Comparison with single-mode fiber
The main difference between multi-mode and single-mode optical fiber is that the
former has much larger core diameter, typically 50–100 micrometers; much
larger than the wavelength of the light carried in it. Multi-mode fiber has higher
"light-gathering" capacity than single-mode fiber. In practical terms, the
larger core size simplifies connections and also allows the use of lower-cost
electronics such as light-emitting diodes (LEDs) and vertical-cavity surface-
emitting lasers (VCSELs) which operate at the 850 nm and 1300 nm wavelength
(single-mode fibers used in telecommunications operate at 1310 or 1550 nm and
require more expensive laser sources. Single mode fibers exist for nearly all
visible wavelengths of light).[2] However, compared to single-mode fibers, the
multi-mode fiber bandwidth-distance product limit is lower. Because multi-mode
fiber has a larger core-size than single-mode fiber, it supports more than
one propagation mode; hence it is limited by modal dispersion, while single mode
is not. The LED light sources sometimes used with multi-mode fiber produce a
range of wavelengths and these each propagate at different speeds. In contrast,
the lasers used to drive single-mode fibers produce coherent light of a single
wavelength. This chromatic dispersion is another limit to the useful length for
multi-mode fiber optic cable. Because of their larger core size, multi-mode fibers
have higher numerical apertures which means they are better at collecting light
than single-mode fibers. Due to the modal dispersion in the fiber, multi-mode
fiber has higher pulse spreading rates than single mode fiber, limiting multi-mode
fiber’s information transmission capacity.
Single-mode fibers are most often used in high-precision scientific research
because the allowance of only one propagation mode of the light makes the light
easier to focus properly.
Jacket color is sometimes used to distinguish multi-mode cables from single-
mode, but it cannot always be relied upon to distinguish types of cable. The
standard TIA-598C recommends, for civilian applications, the use of a yellow
jacket for single-mode fiber, and orange for 50/125 µm (OM2) and 62.5/125 µm
(OM1) multi-mode fiber.[3] Aqua is recommended for 50/125 µm "laser optimized"
OM3 fiber.
Types
Multi-mode fibers are described by their core and cladding diameters. Thus,
62.5/125 µm multi-mode fiber has a core size of 62.5 micrometres (µm) and a
cladding diameter of 125 µm. The transition between the core and cladding can
be sharp, which is called a step-index profile, or a gradual transition, which is
called a graded-index profile. The two types have different dispersion
characteristics and thus different effective propagation distance.[4]
In addition, multi-mode fibers are described using a system of classification
determined by the ISO 11801 standard — OM1, OM2, and OM3 — which is based
on the modal bandwidth of the multi-mode fiber. OM4 (defined in TIA-492-AAAD)
was finalized in August 2009,[5] and was published by the end of 2009 by the TIA.[6] OM4 cable will support 125m links at 40 and 100 Gbit/s.
For many years 62.5/125 µm (OM1) and conventional 50/125 µm multi-mode
fiber (OM2) were widely deployed in premises applications. These fibers easily
support applications ranging from Ethernet (10 Mbit/s) to Gigabit
Ethernet (1 Gbit/s) and, because of their relatively large core size, were ideal for
use with LED transmitters. Newer deployments often use laser-optimized
50/125 µm multi-mode fiber (OM3). Fibers that meet this designation provide
sufficient bandwidth to support 10 Gigabit Ethernet up to 300 meters. Optical
fiber manufacturers have greatly refined their manufacturing process since that
standard was issued and cables can be made that support 10 GbE up to 550
meters. Laser optimized multi-mode fiber (LOMMF) is designed for use with
850 nm VCSELs.
The migration to LOMMF/OM3 has occurred as users upgrade to higher speed
networks. LEDs have a maximum modulation rate of 622 Mbit/s because they can
not be turned on/off fast enough to support higher bandwidth applications.
VCSELs are capable of modulation over 10 Gbit/s and are used in many high
speed networks.
VCSEL power profiles, along with variations in fiber uniformity, can cause modal
dispersion which is measured by differential modal delay (DMD). Modal dispersion
is an effect caused by the different speeds of the individual modes in a light
pulse. The net effect causes the light pulse to separate or spread over distance,
making it difficult for receivers to identify the individual 1's and 0's (this is
called intersymbol interference). The greater the length, the greater the modal
dispersion. To combat modal dispersion, LOMMF is manufactured in a way that
eliminates variations in the fiber which could affect the speed that a light pulse
can travel. The refractive index profile is enhanced for VCSEL transmission and to
prevent pulse spreading. As a result the fibers maintain signal integrity over
longer distances, thereby maximizing the bandwidth.
Comparison
Transmission Standards
100 Mb Ethernet
1 Gb (1000 Mb)
Ethernet
10 Gb Ethernet
40 Gb Ethernet
100 Gb Ethernet
OM1 (62.5/125)
up to 550 meters(SX)
220 meters(SR)
33 meters(SR)
NOT SUPPORTED
NOT SUPPORTED
OM2 (50/125)up to 550 meters(SX)
550 meters(SR)
82 meters(SR)
NOT SUPPORTED
NOT SUPPORTED
OM3 (50/125)up to 550 meters(SX)
550 meters(SR)
300 meters(SR)
100 meters 100 meters
OM4 (50/125)up to 550 meters(SX)
550 meters(SR)
>400 meters(SR)
125 meters 125 meters
Fiber Optic Cables
Main article: Fiber Optic Cables
In practical fibers, the cladding is usually coated with a tough resin buffer layer,
which may be further surrounded by a jacket layer, usually glass. These layers
add strength to the fiber but do not contribute to its optical wave guide
properties. Rigid fiber assemblies sometimes put light-absorbing ("dark") glass
between the fibers, to prevent light that leaks out of one fiber from entering
another. This reduces cross-talkbetween the fibers, or reduces flare in fiber
bundle imaging applications.[50][51]
Modern cables come in a wide variety of sheathings and armor, designed for
applications such as direct burial in trenches, high voltage isolation, dual use as
power lines,[52][not in citation given] installation in conduit, lashing to aerial telephone
poles, submarine installation, and insertion in paved streets. The cost of small
fiber-count pole-mounted cables has greatly decreased due to the high demand
for fiber to the home (FTTH) installations.
Fiber cable can be very flexible, but traditional fiber's loss increases greatly if the
fiber is bent with a radius smaller than around 30 mm. This creates a problem
when the cable is bent around corners or wound around a spool,
making FTTX installations more complicated. "Bendable fibers", targeted towards
easier installation in home environments, have been standardized as ITU-T
G.657. This type of fiber can be bent with a radius as low as 7.5 mm without
adverse impact. Even more bendable fibers have been developed.[53] Bendable
fiber may also be resistant to fiber hacking, in which the signal in a fiber is
surreptitiously monitored by bending the fiber and detecting the leakage.[54]
Another important feature of cable is cable's ability to withstand horizontally
applied force. It is technically called max tensile strength defining how much
force can applied to the cable during the installation period.
Some fiber optic cable versions are reinforced with aramid yarns or glass yarns
as intermediary strength member. In commercial terms, usage of the glass yarns
are more cost effective while no loss in mechanical durability of the cable. Glass
yarns also protect the cable core against rodents and termites.
Power transmission
Optical fiber can be used to transmit power using a photovoltaic cell to convert
the light into electricity.[58] While the efficiency is not nearly that of electricity (the
efficiency of the photovoltaic is around 40 to 50%), it is especially useful in
situations where it is desirable not to have a metallic conductor as in the case of
use near MRI machines, which produce strong magnetic fields.[59]
Two basic cable designs are:
Loose-tube cable, used in the majority of outside-plant installations, and tight-
buffered cable, primarily used inside buildings.
The modular design of loose-tube cables typically holds up to 12 fibers per buffer
tube with a maximum per cable fiber count of more than 200 fibers. Loose-tube
cables can be all-dielectric or optionally armored. The modular buffer-tube design
permits easy drop-off of groups of fibers at intermediate points, without
interfering with other protected buffer tubes being routed to other locations. The
loose-tube design also helps in the identification and administration of fibers in
the system.
Single-fiber tight-buffered cables are used as pigtails, patch cords and jumpers to
terminate loose-tube cables directly into opto-electronic transmitters, receivers
and other active and passive components.
Multi-fiber tight-buffered cables also are available and are used primarily for
alternative routing and handling flexibility and ease within buildings.
1 - Loose-Tube Cable
In a loose-tube cable design, color-coded plastic buffer tubes house and protect
optical fibers. A gel filling compound impedes water penetration. Excess fiber
length (relative to buffer tube length) insulates fibers from stresses of installation
and environmental loading. Buffer tubes are stranded around a dielectric or steel
central member, which serves as an anti-buckling element.
The cable core, typically uses aramidor Glass yarn, as the primary tensile
strength member and rodent protection. The outer polyethylene jacket is
extruded over the core. If armoring is required, a corrugated steel
tape/galvanized steel tape armor is formed around a single jacketed cable with
an additional jacket extruded over the armor.
Loose-tube cables typically are used for outside-plant installation in aerial, duct
and direct-buried applications.
2 - Tight-Buffered Cable
With tight-buffered cable designs, the buffering material is in direct contact with
the fiber. This design is suited for "jumper cables" which 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.
The tight-buffered design provides a rugged cable structure to protect individual
fibers during handling, routing and connectorization. Yarn strength members
keep the tensile load away from the fiber.
As with loose-tube cables, optical specifications for tight-buffered cables also
should include the maximum performance of all fibers over the operating
temperature range and life of the cable. Averages should not be acceptable.
Here are some common fiber cable types;
Distribution Cable
Low Smoke Zero Halogen (LSZH)
Low Smoke Zero Halogen cables are offered as as alternative for halogen free applications. Less toxic and slower to ignite, they are a good choice for many international installations. We offer them in many styles.. Since splicing is eliminated, termination hardware and labor times are reduced, saving you time and money. This cable may be run through risers directly to a
convenient network hub or splicing closet for interconnection.
Single Loose Tube - Indoor Outdoor
SLT-NMA-SJ-UP TO 24FO
1 Outer Sheath (LSZH Jacket)2 Glass Yarn3 Filling Material4 Central Tube5 Optical Fibers up to 24 core (24Core with 2 bundles).
ETK’s innovative line of indoor/outdoor loose tube cables are designed to meet all the requirements of users, can easliy be installed inside the building.
Multi - Loose Tube CableMLT-NMA-SJ-UP TO 192FO
1 Outer Sheath2 Glass Yarn3 Central Strength Member4 Core Wrapping5 Petroleum Jelly6 Optical Fibers7 Buffer Material (PBT)8 Thixotrophic Jelly
Loose tube cable is designed to endure outside temperatures and high moisture conditions. The fibers are loosely packaged in gel filled buffer tubes to repel water. Recommended for use between buildings that are unprotected from outside elements. Loose tube cable is restricted from inside building use.
Aerial Cables/Self-Supporting
MLT-SA(NMA*)-SJ-A-UP TO 48FO *OPT
Aerial cable provides ease of installation and reduces time and cost. Figure 8 cable can easily be separated between the fiber and the messenger. Temperature range ( -20ºC to +70ºC). Various Messenger wire diameters are available according to differt pole span distances.
Hybrid & Composite Cables (SLT & MLT available)
Hybrid cables offer the same great benefits as our standard indoor/outdoor cables, with the convenience of installing multimode and singlemode fibers all in one pull. Our composite cables offer optical fiber along with solid 2x1mm, 2x2.5 and 2x4 power wires suitable for a variety of uses including power, grounding and other electronic controls.
Armored Cable Types
MLT(*SLT)-SA-SJ(DJ)- UP TO 192FO
Reliability and quality
Optical fibers are inherently very strong, but the strength is drastically reduced
by unavoidable microscopic surface flaws inherent in the manufacturing process.
The initial fiber strength, as well as its change with time, must be considered
relative to the stress imposed on the fiber during handling, cabling, and
installation for a given set of environmental conditions. There are three basic
scenarios that can lead to strength degradation and failure by inducing flaw
growth: dynamic fatigue, static fatigues, and zero-stress aging.
Advantages of fiber optics:
1. Extremely high bandwidth – No other cable-based data transmission medium offers the bandwidth that fiber does.
2. Easy to accomodate increasing bandwidth – Using many of the recent generations of fiber optic cabling, new equipment can be added to the inert fiber cable that can provide vastly expanded capacity over the originally laid fiber. DWDM, or Dense Wavelength Division Multiplexing, lends fiber optic cabling the ability to turn various wavelengths of light traveling down the fiber on and off at will. These two characteristics of fiber cable enable dynamic network bandwidth provisioning to provide for data traffic spikes and lulls.
3. Resistance to electromagnetic interference – Fiber has a very low rate of bit error (10 EXP-13), as a result of fiber being so resistant to electromagnetic interference. Fiber-optic transmission are virtually noise free.
4. Early detection of cable damage and secure transmissions – Fiber provides an extremely secure transmission medium, as there is no way to detect the data being transmitted by “listening in” to the electromagnetic energy “leaking” through the cable, as is possible with traditional, electron-based transmissions. By constantly monitoring an optical network and by carefully measuring the time it takes light to reflect down the fiber, splices in the cable can be easily detected.
Disadvantages of Fiber Optics:
1. Installation costs, while dropping, are still high – Despite the fact that fiber installation costs are dropping by as much as 60% a year, installing fiber optic cabling is still relatively costly. As installation costs decrease, fiber is expanding beyond its original realm and major application in the carrier backbone and is moving into the local loop, and through technologies such as FTTx (Fiber To The Home, Premises, etc,) and PONs (Passive Optical networks), enabling subscriber and end user broadband access.
2. Special test equipment is often required – The test equipment typically and traditionally used for conventional electron-based networking is of no use in
a fiber optic network. Equipment such as an OTDR (Optical Time Domain Reflectometer)
is required, and expensive, specialized optical test equipment such as optical probes are needed at most fiber endpoints and connection nexuses in order to properly provide testing of optical fiber.
3. Susceptibility to physical damage – Fiber is a small and compact cable, and it is highly susceptible to becoming cut or damaged during installation or construction activities. Because railroads often provide rights-of-way for fiber optic installation, railroad car derailments pose a significant cable damage threat, and these events can disrupt service to large groups of people, as fiber optic cables can provide tremendous data transmission capabilities. Because of this, when fiber optic cabling is chosen as the transmission medium, it is necessary to address restoration, backup and survivability.
4. Wildlife damage to fiber optic cables – Many birds, for example, find the Kevlar reinforcing material of fiber cable jackets particularly appealing as nesting material, so they peck at the fiber cable jackets to utilize bits of that material. Beavers and other rodents use exposed fiber cable to sharpen their teeth and insects such as ants desire the plastic shielding in their diet, so they can often be found nibbling at the fiber optic cabling. Sharks have also been known to damage fiber optic cabling by chomping on it when laid underwater, especially at the repeating points. There is a plant called the Christmas tree plant that treats fiber optic cable as a tree root and wraps itself around the cable so tightly that the light impulses traveling down the fiber are choked off.