Optic Fibre Networks
The development of the National Broadband Network (NBN) has brought public attention to what the industry have known for years: fibre optic is a critical infrastructure. The NBN is now being described as an infrastructure project, the same as the electricity, water, sewerage, road and rail network.
Fibre optic systems are the backbone of every digital communications system, and the most critical part of the system. Whether it is the fibre optic link from the office to the factory, between buildings at a school, or a network infrastructure for a campus, mine or a broadband network, if you have problems with your optic fibre system, it will always have significant impact on a large portion of your business.
The various optic fibre cores are then packaged together in various core counts and with other materials to become a fibre optic cable. Fibre optic cables come in many different shapes, sizes and varieties, but can be categorised into three broad groups
- Tight buffered
- Loose tube
- Blown fibre
In Australia, all communications cables installed underground must pass the water penetration and UV resistance requirements of AS/CA S008, this is generally the domain of loose tube fibres.
Tight buffered cables, in their various forms, are generally regarded as internal cables. Whilst some cables sold as ‘outdoor’ or ‘indoor/outdoor’ are of tight buffered construction, not all of them meet the water penetration requirements for underground use, and as not legally allowed to be used.
Blown fibre is a specialised product that is commonly installed on large scale private projects with a long lifetime with an anticipated upgrade or expansion requirement, such as universities, councils and mines. It involves installation of empty cables called micro-ducts, full of coloured tubes that look like straws. A blowing head is then connected to the end of the tubes, and various counts and types of fibre optic can be blown down the tube. The fibres can be changed, replaced or upgrade very easily, without the need for installation of new fibre optic cables.
Testing & Commissioning
Testing and commissioning of optic fibre is a precision skill that requires significant amount of training. Fibre optic isn’t as simple as a tester saying “Pass” or “Fail”, and requires precision instruments, with skilled operators, who can setup and interpret the results.
The testing requirements under AS/NZS ISO/IEC 14763.3:2012 are quite specific, but should be regarded as a “baseline” test for fibre optic installations. It is very easy for a fibre to pass these tests, but not actually perform as designed or intended, resulting in a lot of lost time and finger pointing.
Testing can be conducted using Light Source Power Meters (LS/PM), Optical Loss Test Sets (OLTS) or Optical Time Domain Reflecometers (OTDR).
Many of our clients, including NBN Co, BHP, Rio Tinto, FMG, University of WA, Curtin University and the Public Transport Authority have testing requirements that go above and beyond the requirements of AS/NZS ISO/IEC 14763.3:2012. This can be a simple as requiring OTDR traces in addition to the standard LS/PM, having specific referencing methods or having significantly lower loss requirements per event.
Fault Finding and Repairs
Because of the critical nature of fibre optic cables, fault finding and the subsequent repairs must be done permanently, quickly and efficiently to reduce short term and long term downtime.
Our highly skilled operators can use our specialised test equipment to find the location of a fault within minutes, most often to a precise location within a few minutes.
Once we have found the location and cause of a fault, a decision can be made as to the best repair method to reduce downtime and ensure long term reliability. If it is an issue that is likely to re-occur, and replacement cable might be recommended and a temporary repair conducted, but often a permanent repair is the best solution.
Using one of our core-alignment fusion splicers, our technician can join two optic fibres with losses as low as 0.01db, and install it into various different enclosures to product the joint into the future.