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An optical cable is one of the cheapest and easiest ways to connect your devices together, in order to transfer digital video or sound signal. Also known as SPDIF or Toslink, an optical cable consists of fiber optic that transfers light, rather than an electrical signal as a digital coaxial cable would do for example. This means they are less prone to electrical interference. Optical cables are easy to connect and use. They have a plug on each end of the cable to prevent dirt and dust getting into it, which needs to be removed before use, and replaced when not in use. The socket on your player or amplifier will normally have a spring operated gate that automatically opens when the plug is inserted and closes when the cable is removed. There are many different types of cables available, and which one to choose really depends on what you will be using the cable for.
What are the advantages of optical cables?
Because the digital audio signal is transferred by light rather than an electrical signal, they are less susceptible to interference from nearby electrical sources. It also means that the cable is thinner, and it's easier to hide under carpets/floooring. They are also more flexible and simple to run between your devices such as DVD Player, Playstation 3, XBox or Sky box. They are available in numerous different lengths from 0.5m right up to 50m, and are especially suited for longer cable runs as they perform slightly better than a digital coaxial cable.
Which cable do I need?
Any optical cable provides the same function, no matter what the brand is. Some cables have been designed specifically for certain equipment such as a PS3 or XBox 360 to offer audio advantages, and also to match the colours and style of the console. Any optical cable will be able to do the job though.
Does Quality Matter?
There are some people who think that a more expensive, branded cable offers higher sound quality, but in our opinion the most important thing a branded cable offers is the higher build quality. This is especially important with optical as the cable itself is quite thin and you ideally want the toughest you can get. Whilst you don’t want to compromise the thinness benefits of optical cables, it is always advisable to go for a cable with a higher sleeve thickness to prevent any potential damage.
What are the different types of fiber optic cables?
There are two basic types of optical cables used for data and communications: singlemode and multimode. The main differences are core size and the distance signals that can be carried. Fiber cable is measured by its core and cladding diameter in micrometers (µm).
Multimode
Multimode optical fiber cables have a larger core than single-mode and are able to send multiple light pulse signals at once. Although this allows more data to move through the cable at any given time, it creates a high dispersion rate and limits the distance that data is able to travel. For this reason, multimode fiber is primarily used for wiring within a local area network (LAN), such as an office space.
Multimode Fiber has a relatively wide core size of either 62.5 µm or 50 µm. It transmits infrared light commonly from light-emitting diodes (LEDs). Generally, multimode cable is used for communication over short to midrange distances, such as within a building or on a small campus. Typical multimode fiber links are suitable for distances under 2,000 feet.
Multimode fibers are identified by the OM (optical mode) designation outlined in the ISO/IEC 11801 standard:
OM1 - Fiber with 200/500 MHz-km overfilled launch (OFL) bandwidth at 850/1300nm (typically 62.5/125 µm fiber)
OM2 - Fiber with 500/500 MHz-km OFL bandwidth at 850/1300nm (typically 50/125 µm fiber)
OM3 - Laser-optimized 50 µm fiber having 2000 MHz-km effective model bandwidth (EMB, also known as laser bandwidth), designed for 10 Gbps transmission
OM4 - Laser-optimized 50 µm fiber having 4700 MHz-km EMB bandwidth designed for 10 Gbps, 40 Gbps and 100 Gbps transmission.
Single-Mode
Single-mode cables are designed to carry only one ray of light at a time. These cables make use of a smaller core diameter than multimode, allowing them to maintain their signal strength with less attenuation. Single-mode fiber is designed for long-distance transmission of data and has a much higher bandwidth than multimode fiber. As a result, it is commonly used by telecommunications companies and cable TV providers to establish their wide area network (WAN). Singlemode Fiber has a narrower core size of 8.3 µm. It transmits infrared light from lasers and delivers twice the bandwidth throughput of multimode cable and can provide 50 times more distance than multimode. On the flip side, it costs more than multimode cable. Duplex singlemode cable is commonly used in long-haul network connections.
Important:
Mixing different sizes or types of fiber optic cable is not recommended; doing so will result in distortions, signal degradation and severely limited distances.
How far can a fiber optic cable carry a signal?
The distance limit is dependent on the style of cable, the wavelength and the network itself.
Typical ranges are about 984 ft. for 10 Gbps multimode cable and up to almost 25 miles for singlemode cable. If a longer span is required, optical amplifiers or repeaters are used to ensure signal integrity over the full distance.
Conclusion
Optical fiber network cables have several advantages over the traditional electrical, copper wiring. In addition to offering greatly increased bandwidth and speed, optical fiber is capable of transmitting a signal over much greater distances before a repeater is needed. The cables are also resistant to cross talk and free of electromagnetic interference. Single-mode cables use a small cable diameter and a single light ray to transmit a signal rapidly over long distances, and are ideal for sending information to users across a WAN. Multi mode cables are designed for simultaneous transmission of multiple signals, making them better-suited for LANs. Decide between indoor and outdoor cables to maximize the longevity of a network setup, and investigate armored cables, if needed. With proper installation, optical fiber network cables can dramatically improve the rate and performance of data transmission for a network.
