Not so long ago it was copper wire that was the primary choice for sending communications signals in offices, home and different locations. But fibre optics has taken over that spot, and is now one of the mostly widely used and trusted of all the cabling methods.

Fibre optic cabling first entered the world of commercial installation all the way back in 1977. A lot has changed since then, including how fibre optic is used.

The goal of this post is to help you understanding the fibre optic cabling basics, including the different types and why you should choose it over the other options of network cabling available today.

Fibre Optic Cabling: The Basics

In many ways fibre optic cabling may seem very similar to copper wire. The important difference is that fibre optic cables use light pulses to send information instead of electronic pulses. The different in speed and reliability of these pulses is what has made fibre optic the preferred choice.

What’s involved in a fibre optic chain setup?

Let’s take a deep dive into the different components of a fibre optic chain to get a better idea of how it works and how it might fit into your network along with existing infrastructure.

At one side of the cable system you have the transmitter, and this is where the information is sent down the line. This transmitter can integrate with the existing copper wire and interpret those electronic pulses. It then converts this information into light pulses so that they can be sent further. This is done with a light-emitting diode (LED) or an injection laser diode (ILD).

These pulses of information are sent down the cable line using a lens to funnel the light.  This light is near infrared and is most often 850nm for shorter distances and 1,300nm for longer distances on Multi-mode fibre. For single-mode fibre it will be 1300nm and 1,500nm is used for longer distances.

If you are finding that difficult to visualize, just imagine that fibre cable is like a long cardboard roll, like you’d find inside a roll of paper towel. The line of this cable is coated with a mirror, which means that if you shined a flashlight into one end it would be reflected out at the far end – even if the cable bends around corners along the way.

Understanding Total Internal Reflection

The reason light can pulse up and down the fibre optic cable line is because of a concept called “total internal reflection”.

This concept explains that when the angle of incidence is beyond a critical value, light cannot escape out from the glass and instead will bounce back in.

Fibre-optic strands use this principle in order to allow for the transmitting of information through light pulses. For this to work, the core of the cable must be a clear and pure material in order to properly move the light or near-infrared light (850nm, 1300nm and 1500nm).

If the light only needs to travel over short distances then the core can be made from plastic. However, it is much more common to find cables made from glass.

Glass optical fibre cables are nearly always made from pure silica, although other materials such as fluorozirconate, fluoroaluminate and chalcogenide glasses may be used for longer-wavelength infrared applications.

The Advantages of Fibre Optic Cabling

Now that we’ve got a bit of a sense of what we’re actually talking about when referring to fibre optic cable, let’s take a look at some of the advantages that this type of cabling offers over the alternatives:

  • High Speeds: Since information is being transmitted as light, it can move much faster than other forms of cabling that rely on electrical pulses
  • Large Bandwidth: The fibre optic cable setup allows for a large carrying capacity of data.
  • Transmission Distance: Signals can be sent further through fibre optic without needing any other method to strengthen the signal along the way.
  • Less Interference: Fibre optic cables have a stronger resistance to electromagnetic noise that may come from nearby cabling or from other sources of interference such as radios and motors.
  • Low Maintenance Cost: Because of their reliability and low maintenance requirements, you can expect to spend less in the long run to keep your cable infrastructure running.

Which industries are switching to fibre optic cabling?

Telephone companies were one of the early adopters of fibre optic. Today’s companies will primarily rely on fibre optic instead of copper wire as the backbone of their architecture and for ensuring a stable long-distance connection.

Any large institution, such school campuses, office buildings, industrial plants and large commercial properties will definitely prefer to rely on the more stable and quicker transmitting speeds available with fibre optic.

Fibre optic is also becoming increasingly common for residential homes in urban centres, and is becoming available even in rural areas as networks grow in size.

What types of fibre optic cable can you choose from?

When dealing with fibre optic cabling, there are three main types to consider:

Single-Mode Cable

This style of fibre optic cable is made of a single strand of glass fibre that has a diameter of 8.3 to 10 microns and only one mode of transmission. Single-mode has a fairly narrow diameter, through which only one mode will propagate (typically 1310 or 1550 nm). This type of cable comes with a higher bandwidth than multimode fibre, but the trade-off is that it needs a light source with a narrow spectral width.

Single-mode fibre is used in many applications where data is sent at multi-frequency (WDM Wave-Division-Multiplexing) so only one cable is needed. The benefit is a higher transmission rate and as much as 50 times more distance than multi-mode, but at a greater expense.

Single-mode fibre has a much smaller core than multi-mode. This style of construction is effective in removing any distortion that could result from overlapping light pulses, and this is why single-mode provides the least signal attenuation and the highest transmission speeds of any fibre cable type.

With single-mode, only the lowest order bound mode can propagate at the wavelength of interest typically 1300 to 1320 nm.

This type of cable can also sometimes be called mono-mode optical fibre, single-mode fibre, single-mode optical waveguide or uni-mode fibre.

Multi-mode Cable

This type of cable has a slightly larger diameter, often coming closer to the  50 to 100 micron range for the light carry component. Often when multi-mode fibre is used, two fibres are used (WDM is not normally used on multi-mode fibre).

The benefit of multi-mode comes in high bandwidth at high speeds (10 to 100MBS – to 275m to 2km) over medium distances. The light waves are sent into numerous paths, also known as modes, when they are moving through the cable’s core, typically 850 or 1300nm. Typically multimode fibre core diameters can be found in 50, 62.5, and 100 micrometres.

One important thing to consider is that for cable runs that are longer than 3000 feet (or 914.4 meters) then there can be some signal distortion at the receiving end from the multiple paths of light, and this can cause unclear or incomplete data transmission. For this reason, network cabling designers are more likely to request for single-mode fibre in new applications using Gigabit and beyond.

3. Plastic optical fibre (POF)

Plastic optical fibre is a fairly new innovation that uses cables with a plastic core. This comes with a cheaper cost at the sacrifice of speed when transmitting over long distances. For a short and simple setup, POF cables might be a good fit.

A reliable part of a secure and efficient network cabling setup

If you aren’t running fibre optic cables yet then there’s no better time than the present to get started! Give yourself added peace of mind that your infrastructure is going to be as reliable tomorrow as it is today.