Optical fibre and cables: interesting facts about Sirocco Extreme | Prysmian

SiroccoExtreme

Optical fibre and cables: interesting facts about Sirocco Extreme


Do you know what's behind a reliable, fast, high-performance Internet connection? 

Optical fibre. We often hear about it, especially when we consult the offers of telephone operators, but what is the optical fibre really and how does it work?

What is optical fibre?

An optical fibre is a thin, flexible filament of transparent material, usually glass, able to transmit light signals over long distances and at high speeds, averaging over 100 gigabits per second — like downloading an entire HD movie in one second.

The light travelling in the optical fibre is reflected by the fibre’s inner core, thereby maintaining its intensity and quality. In addition, the optical fibre is thinner than a human hair, with a diameter of about 0.1 millimetres. 

It was invented in 1952 by Indian physicist Narinder Singh Kapany and today has multiple applications in medicine, art, military and space communication. In fact, one of its main advantages is that it allows the transfer of huge amounts of data in a very short time, ensuring a fast and stable Internet connection, which is essential in many different areas.

Optical cable: what is it used for?

To enable its use, the optical fibre needs to be inserted inside an optical cable. To date, an optical cable can contain between 1 and 6,912 optical fibres and is designed to protect them adequately, also depending on where and how it is installed.

Each fibre contained in a cable has to be colour-coded, so that each fibre can be uniquely identified at both ends of the cable. The colour-based recognition system is very similar to that used for electrical wires. 

In fact, an optical cable usually contains more than one fibre, as the need for optical fibres is high and the spaces that can accommodate them are limited. To enable the installation of multiple fibres in a single duct, it is essential to reduce as much as possible the diameter of fibres and cables. 

In addition, a higher fibre density produces other benefits, such as reduced costs — including packaging and transportation costs —, faster installations, and a lower carbon footprint

However, it is essential that fibre performance is not compromised when size is reduced and density increased, and that compatibility with existing networks is guaranteed, meaning that the thin fibre can be joined to standard-diameter fibres.

Optical cables and fibre according to Prysmian

To date, Prysmian has been able to adapt its ability to develop cables that can bend without damaging the fibres inside them to the new need for use in small spaces, and has thus designed a new range of cables that are flexible and, at the same time, feature a reduced diameter. 

A standard fibre is composed of: 

  • a glass core with a diameter of 125μm, 
  • a protective primary plastic coating, 
  • a transparent secondary coating, 
  • a layer of UV-cured coloured ink to reach the final diameter of the coloured fibre.

In the 1990s, Prysmian introduced for the first time the ColorLock fibre coating system — later surpassed in quality by its successor ColorLock-XS — which eliminated the need for the outer additional layer by using a secondary plastic coating that included the colour pigments already. This enabled the cable diameter to be reduced.

Subsequently, in 2009, the Group was able to further reduce the thickness of the primary and secondary coatings through the combination of an improved primary coating and the ColorLock-XS technology. The overall outer diameter was thus reduced to 200μm, saving a third of the standard fibre’s cross-section.

Finally, in 2019, the Company introduced a 180μm bend-resistant fibre, eliminating half the cross-section of the standard fibre, with a glass core that still has a standard size of 125μm and is therefore compatible with the products.

The Sirocco optical cable range

This is how Prysmian's SiroccoHD and Sirocco Extreme cable range came about. These ultra-thin cables use bend optimised BendBright XS single-mode fibres, first 200μm and then 180μm in size. With their high fibre count and reduced diameter, SiroccoHD and Sirocco Extreme cables are designed for installation through air blowing in high-density access networks, FTTx and 5G infrastructures. 

The Sirocco family cables allow: 

  • more fibres to be installed in congested duct spaces; 
  • smaller ducting to be used for new installations; 
  • easier installation, with fewer specialist engineers required; 
  • installation costs to be reduced; 
  • the use of raw materials to be minimised; 
  • network operators' operating costs to be reduced more generally; 
  • a lower environmental impact.

All the features of Sirocco Extreme with 864 fibres

The latest addition to the Prysmian cable family is Sirocco Extreme with 864 fibres

The Sirocco Extreme 864f microduct cable contains 864 fibres in a 9.8 mm diameter, offering an unprecedented fibre density of 11.5 fibres per mm2. It can be installed in a 12mm duct, pushing the boundaries of what can be done in the field of telecom cable systems. Prysmian's Sirocco Extreme microduct cables use the bend insensitive BendBrightXS 180μm single-mode fibre (ITU-T G.657.D, G.657.A2), which ensures compatibility with existing G.652 fibres and readiness for evolved systems.

The versatility of BendBrightXS optical fibre

The BendBright fibre technology has received the FTTH Innovation Award as it is currently the only 180μm reduced diameter optical fibre already colour-coded, designed to address the challenges of deploying fibre optic networks in increasingly demanding environments, without compromising performance or reliability. 

With its ultra-thin diameter, BendBright offers unmatched flexibility and bend resilience. Its unique features make it ideal for a wide range of applications, including urban, rural, and indoor environments, where space constraints and challenging conditions present significant barriers to traditional optical fibre solutions.