Plastic vs glass optical fibre – what’s the difference and what are they used for?

It’s probably fair to say that your life, as you know it, would be completely impossible if you couldn’t get online. Ok, maybe not impossible, but your daily routine would look very, very different indeed. But what do you really know about the technology that facilitates such a massive part of your life, work, social life, family and friends, even your hobbies and passions? Ever heard of plastic or glass optical fibre? Each one is different, with very different applications.



With optical fibre, it’s all about light

Before we delve into the details and look at the differences between the various types of cable, let’s clarify a few of the basics. Put (very) simply, fibre optic connectivity is possible because of light pulses that are run through an extremely thin filament in a cable, with emitters and receivers at either end. Those receivers interpret the presence of light as a “one” and its absence as a “zero”. In other words, the cables are able to speak binary code. But we’re talking about millisecond time intervals here. By laying optical fibre cables over very long distances, coupled with the fact that light can travel at 300,000 km/second, optical fibre is one of the preferred ways of transmitting large amounts of data today.



Plastic optical fibre: cheap and works well with light

Plastic optical fibre takes its name from its material – it’s hardly rocket science! Plastic produces a physically highly flexible cable and is the most conducive solution when fibre has to be laid in curves or around corners. It’s also relatively cheap to make, so it’s suitable for applications where budgets are somewhat limited. Due to plastic’s refractive index, however, the signals (and therefore data) it carries can experience cuts and losses over very long distances.


This drawback of using plastic optical fibre means it can be an appropriate option in situations where data transmission isn’t absolutely vital, but in situations where it is, such as highly-precise medical and surgical applications, for example, another solution is generally preferred. Despite this, plastic optical fibre is being used for connectivity applications in Industry 4.0, as long as connections are over shorter distances or the scope is somewhat limited.



Glass optical fibre: more expensive, but also more stable, and better over long distances

Any deficiencies of plastic optical fibre are more than made up for by glass optical fibre. Glass has a refractive index and structural characteristics that allow light pulses to be transmitted over much greater distances. Another virtue of glass optical fibre is that it prevents there from being as many losses or inconsistencies in signals that you sometimes get with plastic optical fibre. Of course, unlike plastic, glass is much more fragile and susceptible to breaking, so it’s not suitable for intricate layouts.


Similarly, material costs are a little higher, compared to plastic optical fibre. However, glass has become the preferred transmission method when considerable bandwidth, serious stability and linking up geographically very distant points via submarine optical fibre cables is required, for example. Logically, that’s exactly what makes it the “favourite” connectivity method in the telecommunications market.


Although very different in their physical structures and potential applications, plastic and glass optical fibre nicely balance and complement one another in terms of their intrinsic positives and negatives. That’s why both are versatile, practical and convenient when it comes to meeting different needs in their own ways, and not necessarily just for the world of connectivity, but simply for transmitting data at very high speeds.

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