The question of ‘which fibre cable to choose’ is one that we are being asked more and more frequently. Many installers are slowly but surely making the switch from copper to fibre-optic cable. Fibre optic systems are able to deal with the growing demands from users for greater bandwidth and super fast connection speeds. Some time ago we explained key choices to use copper or fibre-optic solutions, and we provided a few hints about alternatives to copper in another blog post. However, not all distributors and installers understand which fibre-optic cable would be best for a particular purpose.
Multimode or Singlemode?
We’ve briefly written about the singlemode or multimode question here in the past. Ultimately, there are two types of fibre-optic glass, multimode and singlemode. The difference between the two is how the cable carries the light. We’ve also previously explained the difference between the two for those considering the singlemode or multimode question. Essentially singlemode allows only one core of light to propagate, whereas multimode allows multiple modes of light (hence the name).
Singlemode fibre cables have lower attenuation, meaning they can carry signals faster over greater distances, making them ideal for long-haul networks, where signals need to travel large distances. Multimode fibre cables allow more signals to be transmitted due to the fact that they have a larger core, but this can often mean reduced signal quality, especially over longer distances. Multimode fibre cables are better for locations where communications only need to be sent over shorter distances, such as within premises.
Further complicating things are the various glass fibre subtypes, including OM1-4, and Singlemode G652 / G657A.
Multimode cables come in 4 distinct types: OM1, OM2, OM3, and OM4. OM1 fibre cables have a core size of 62.5 micrometers (µm), and is commonly used inside buildings for installations where the lengths don’t exceed a few hundred meters. OM2, OM3, OM4 cables have a core size of 50 micrometers (um), and are commonly used inside buildings for higher bandwidth installations between 80m and 600m.
Singlemode cables are either G652D or G657A.1. G652D offers a reduced water peak which enables the fibres to operate between 1310nm and 1550nm supporting Coarse Wavelength Division Multiplexed (CWDM) transmission. G657A.1 offers an improved bend sensitivity performance. It is designed to allow fibre to be flexed without affecting glass performance. It is common within cable TV and FTTH applications to encounter areas where reduced bend sensitivity is critical, and this is where G657A.1 is of real benefit.
Tight Buffered, Central Loose Tube, or Multi Loose Tube?
Loose tube fibre cables protect the fibre core, cladding, and coating by enclosing everything within semi-rigid protective sleeves or tubes. Many loose tube cables also have a gel that surrounds the fibres to protect them from excess moisture, and allows the tubes to expand and contract with temperature changes.
Where larger fibre counts are needed, Multi Loose Tube fibre cables are often used, combining multiple loose tubes around a rigid central (usually glass) strength member.
The problem for most loose tube cables is when they need to be manipulated such as being routed around bends in the cable run. Too much strain can damage the cable by forcing fibres to emerge from the gel. G657A.1 glass would be the ideal choice in this area.
Tight buffered cables are often used indoors, as more bends usually exist in indoor cable runs. Tight buffered fibre cables are usually robust enough to handle most indoor applications, including LAN/WAN connections.
LSZH, PE, SWA or CST?
Like most copper cables, the sheathing type required will depend upon where the cable is to be used. For both internal and external use, LSZH sheathing is used for most fibre cables. Where an element of protection is required PE sheathing is often used, usually in external environments. Should further protection be needed, steel wire armour can be used in direct burial situations, and corrugated steel tape is used when rodent protection is required.
So, Which Fibre Cable Should I Use?
In a nutshell, as singlemode fibre cables can carry data faster over greater distances, this makes them ideal for longer distance fibre runs, such as those found within university campuses and telecommunications networks.
Multimode fibre cables are better for within premise installations, such as fibre backbones for company WAN/LAN networks, especially if 802.11ac or newer WiFi access points are needed.
Lastly, it’s recommended not to combine singlemode and multimode fibre cables. The two formats are not easy to combine, and require an additional piece of hardware to do any sort of translation.
If you have any queries about which fibre cable from our fibre-optic cable range you need, contact our sales team now on 0115 9724483 or firstname.lastname@example.org