Fiber Optics
A fiber optic system may have very high bandwidth, sometimes operating
at data rates of 10Gb/s, equivalent to more than 120,000 standard
telephone calls over one pair of optical fibers (one transmitting and
one receiving). Under Lab conditions, data rates as high as 10 terabits
per second have been demonstrated (150 million telephone calls).
Datacomms type fibers have a lower information carrying capacity but are
capable of 1Gb/s with some 10 Gigabit systems now in use.
Due to the
low attenuation (or signal loss) exhibited by optical fibers, signals
can be transmitted very long distances. In subsea telecommunications,
distances of up to 280km have been used without the requirement for
repeaters or boosters. Repeater systems can span as much as 10,000 to
15,000km, where optical amplifiers are used to boost the signal levels
typically around every 80km or so,.
Datacomms optical fibers have higher losses but can easily cope with the
longest cable runs likely to be encountered in LANS.
An optical fiber is extremely light, a 2km bobbin would only weigh
approx. 1lB, therefore it is ideal for use in applications where weight
is critical. Equally, a coated optical fiber is only 250 microns (a
quarter of a millimeter) in diameter, a 12 core (12 fiber) cable may be
less than 8mm in diameter for indoor use.
Fiber Optic Cabling Is Secure
- Operational fibers do not radiate any signal, the
optical signal is completely contained in the middle of the fiber.
This means that fibers are frequently used for applications where
data security is important such as military and government
communications.
- Even if attempts are made to ‘tap into’ a fiber
optic cable by isolating a bare fiber and putting a tight bend onto
it so that some of the signal escapes, this intrusion can be
detected by monitoring the power of the transmitted signal, and
located using an OTDR technique (Optical Time Domain Reflectometer).
Fiber Optic Cabling Is Safe
- A fiber optic communications cable does not need
to carry any electrical current.
- It is possible to construct completely
non-metallic cables so that full electrical isolation can be
achieved, particularly important in the Electric supply industry.
There are no risks of short circuits generating sparks which may
ignite explosive gases etc.
- Non-metallic cables are not prone to lightning
strikes in exposed areas.
- All these intrinsically safe characteristics have
led to the widespread use of fiber optics in hazardous environments
such as oil refineries, chemical works, coal mines etc.
Fiber Optic Cabling Is Environmentally friendly
- A Compared to copper communications cables, there
is little use of resource in manufacturing, transporting and
installing fiber optic cables because of the lightweight, compact
nature of optical fibers.
Fiber Optic Cable Has No scrap value
- Fiber optic cable is worthless as scrap and
therefore not worth stealing unlike copper telecoms cable.
Fiber Optic Cabling Is Future-proof
- Any fiber optic system currently installed will
only be using a very small fraction of the potential information
carrying capacity of the fiber. Therefore, as demand for
communications capacity increases the system can be upgraded by
attaching more sophisticated transmission equipment.
Fiber Optics Are Cost effective
- Many people view fiber optics as being very
expensive, but for any application where there is a lot of data to
move over long distances then fiber is likely to provide the
cheapest solution.
- There is a general downward trend in prices
of fiber optics cabling, components, tools and installation
equipment. However, the transmission equipment which converts
electricity into light and back again is still relatively expensive.
As prices continue to fall, and the price of copper continues to
rise, fiber optics will become the most cost-effective solution for
more and more applications – bringing all the other benefits as
well.