What is Fiber Optics?

What is Fiber Optics?

Fiber optic cable in essence, is a hair-like glass conduit that carries virtually any type of signal from one point to another at light speed. In case you are wondering why light traveling through fiber optic cable does not actually travel at true light speed, it is because the glass that makes up fiber optic cable is denser than the vacuum of outer space where light can travel without disruption. Needless to say, a fiber optic light signal is still much faster and far superior to a copper based signal, which is why it has become so popular in the cable television, telecommunications and computer networking. Unlike copper based signals, fiber signals are not affected by external power sources or surges and there is no need for shielding or grounding.

How are Fiber Optics used today?
Today, practically every communication network contains fiber optics. In most cases, fiber optics are used because of their convenience. Fiber optic cable allows network builders to divide their network into smaller service areas that prevent large numbers of customers from being affected in an outage. The result is better service and customer relations. Fiber optic cable also gives them a fast return path which they use for internet and telephone connections, thereby increasing their revenue potential.

Local Area Networks (LANs) use fiber optics primarily in the backbone of the network, but the use of fiber optics to the desk is increasing. The LAN backbone often needs longer distance transmissions and more bandwidth than copper cable
is capable of providing. Fiber easily offers the higher bandwidth needed to prepare the network for the much higher speeds projected for the near future.

The use of fiber optics is not just limited to communication networks. Cable and telephone providers often use fiber for its distance capabilities. Distance is also an advantage to industrial plants that use vast amounts of fiber primarily for its noise immunity. Utilities also prefer fiber for noise immunity, security and high bandwidth properties. The military uses fiber because it’s nearly tap-proof and impossible to jam. Fiber is even used by the aviation and aerospace industries because of its smaller size and weight.

What are the advantages of Fiber Optics over Copper wire?
Fiber’s extra distance capability and seemingly unlimited data rate makes it possible to do things not possible with copper wire. For example, you can install all the electronics for a network in one communications closet for a building and run straight to the desk with fiber. With copper,
you can only transmit about 90 meters (less than 300 feet), thus requiring more telecom closets in each building. With fiber, you only need passive patch panels locally to allow for moves. Upgrades can be rather difficult with copper wire, but not with fiber because the real capacity of fiber is only partially utilized at today’s network speed. Many use fiber to connect all their central offices and long distance switches because it has thousands of times the bandwidth of copper wire and can carry signals hundreds of times further before needing a repeater. The cable and telephone providers use fiber because it gives them greater reliability with the opportunity to offer new services, like digital phone service and internet connections. They also use fiber for economic reasons, but their cost justification requires adopting new network architectures to take advantage of the fiber’s strengths.

Where will Fiber Optics take me in the next 20 years?
If you are looking for a career in fiber optics, there are numerous general and industry specific courses available to you. What can you expect if you choose a career in Fiber Optics?
To start with, plenty of great paying jobs spanning over every industry imaginable. Hundreds of thousands have already trained for careers in Fiber Optics but in the near future, industry experts believe that millions of workers will be needed. With gigabit and ten gig Ethernet already spreading through even the smallest of commercial networks, it appears that industry experts are right-on with this call. Get involved today for a brighter tomorrow!

Uses

Communication
Main article: Fiber-optic communication
Optical fiber can be used as a medium for telecommunication and computer networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables. This allows long distances to be spanned with few repeaters.

The per-channel light signals propagating in the fiber have been modulated at rates as high as 111 gigabits per second (Gbit/s) by NTT, although 10 or 40 Gbit/s is typical in deployed systems. In June 2013, researchers demonstrated transmission of 400 Gbit/s over a single channel using 4-mode orbital angular momentum multiplexing.

Each fiber can carry many independent channels, each using a different wavelength of light (wavelength-division multiplexing (WDM)). The net data rate (data rate without overhead bytes) per fiber is the per-channel data rate reduced by the FEC overhead, multiplied by the number of channels (usually up to eighty in commercial dense WDM systems as of 2008). As of 2011 the record for bandwidth on a single core was 101 Tbit/s (370 channels at 273 Gbit/s each).[30] The record for a multi-core fiber as of January 2013 was 1.05 petabits per second. In 2009, Bell Labs broke the 100 (petabit per second)×kilometer barrier (15.5 Tbit/s over a single 7,000 km fiber).

For short distance application, such as a network in an office building, fiber-optic cabling can save space in cable ducts. This is because a single fiber can carry much more data than electrical cables such as standard category 5 Ethernet cabling, which typically runs at 100 Mbit/s or 1 Gbit/s speeds. Fiber is also immune to electrical interference; there is no cross-talk between signals in different cables, and no pickup of environmental noise. Non-armored fiber cables do not conduct electricity, which makes fiber a good solution for protecting communications equipment in high voltage environments, such as power generation facilities, or metal communication structures prone to lightning strikes. They can also be used in environments where explosive fumes are present, without danger of ignition. Wiretapping (in this case, fiber tapping) is more difficult compared to electrical connections, and there are concentric dual-core fibers that are said to be tap-proof.

Fibers are often also used for short-distance connections between devices. For example, most high-definition televisions offer a digital audio optical connection. This allows the streaming of audio over light, using the TOSLINK protocol.

Advantages over copper wiring
The advantages of optical fiber communication with respect to copper wire systems are:

Broad bandwidth
A single optical fiber can carry 3,000,000 full-duplex voice calls or 90,000 TV channels.

Immunity to electromagnetic interference
Light transmission through optical fibers is unaffected by other electromagnetic radiation nearby. The optical fiber is electrically non-conductive, so it does not act as an antenna to pick up electromagnetic signals. Information traveling inside the optical fiber is immune to electromagnetic interference, even electromagnetic pulses generated by nuclear devices.

Low attenuation loss over long distances
Attenuation loss can be as low as 0.2 dB/km in optical fiber cables, allowing transmission over long distances without the need for repeaters.

Electrical insulator
Optical fibers do not conduct electricity, preventing problems with ground loops and conduction of lightning. Optical fibers can be strung on poles alongside high voltage power cables.

Material cost and theft prevention
Conventional cable systems use large amounts of copper. In some places, this copper is a target for theft due to its value on the scrap market.

Sensors
Fibers have many uses in remote sensing. In some applications, the sensor is itself an optical fiber. In other cases, fiber is used to connect a non-fiberoptic sensor to a measurement system. Depending on the application, fiber may be used because of its small size, or the fact that no electrical power is needed at the remote location, or because many sensors can be multiplexed along the length of a fiber by using different wavelengths of light for each sensor, or by sensing the time delay as light passes along the fiber through each sensor. Time delay can be determined using a device such as an optical time-domain reflectometer.

Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the property to measure modulates the intensity, phase, polarization, wavelength, or transit time of light in the fiber. Sensors that vary the intensity of light are the simplest, since only a simple source and detector are required. A particularly useful feature of such fiber optic sensors is that they can, if required, provide distributed sensing over distances of up to one meter. In contrast, highly localized measurements can be provided by integrating miniaturized sensing elements with the tip of the fiber. These can be implemented by various micro- and nanofabrication technologies, such that they do not exceed the microscopic boundary of the fiber tip, allowing such applications as insertion into blood vessels via hypodermic needle.

Extrinsic fiber optic sensors use an optical fiber cable, normally a multi-mode one, to transmit modulated light from either a non-fiber optical sensor—or an electronic sensor connected to an optical transmitter. A major benefit of extrinsic sensors is their ability to reach otherwise inaccessible places. An example is the measurement of temperature inside aircraft jet engines by using a fiber to transmit radiation into a radiation pyrometer outside the engine. Extrinsic sensors can be used in the same way to measure the internal temperature of electrical transformers, where the extreme electromagnetic fields present make other measurement techniques impossible. Extrinsic sensors measure vibration, rotation, displacement, velocity, acceleration, torque, and twisting. A solid state version of the gyroscope, using the interference of light, has been developed. The fiber optic gyroscope (FOG) has no moving parts, and exploits the Sagnac effect to detect mechanical rotation.

Common uses for fiber optic sensors includes advanced intrusion detection security systems. The light is transmitted along a fiber optic sensor cable placed on a fence, pipeline, or communication cabling, and the returned signal is monitored and analyzed for disturbances. This return signal is digitally processed to detect disturbances and trip an alarm if an intrusion has occurred.

Power transmission
Optical fiber can be used to transmit power using a photovoltaic cell to convert the light into electricity.While this method of power transmission is not as efficient as conventional ones, 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. Other examples are for powering electronics in high-powered antenna elements and measurement devices used in high-voltage transmission equipment.