Internet Guide Logo

Optical Fiber

Last Edit: 22/05/17

bullet Introduction

Optical fiber - more commonly referred to as fiber-optic - is a hair thin artificial fiber, which is capable of providing higher data transmission standards (when compared to copper based communication networks). Simple put, fiber-optic communication works by transporting light, and it achieves this by creating a technique named 'total internal reflection'. Total internal reflection is an optical phenomenon where light bounces when directed at a specific angle. Fiber-optics are hair thin and are bunched together to form a cable made from transparent silica glass (sometimes plastic). Fiber-optic cables are typically comprised of cladding, a core (where the light is reflected) and coating to protect the core. Fiber-optic cables come in single mode, plastic optical fiber and multimode configurations. The method of transmitting light down fibre optic cable is always being improved upon; the University College London have managed to send data via fibre optic cable at 1.120 terabits per second.

Total internal reflection, an image showing light bouncing at an angle, as what happens in fiber optic communication systems

Total internal reflection: as the light bounces it can be transported great distances and without the light current suffering from serious attenuation (a gradual lowering of intensity) when compared to electrical cable systems; such as BT's aging copper landline telephone network. Fiber-optic, surprisingly, is not a modern discovery: using reflected light as a means of communications was demonstrated in the 1800's. The issue was finding a reliable way of implementing the technique. The current fiber-optic cable was invented in the 1970's.

Fiber-optic broadband networks are slowly being launched across the United Kingdom, and is sometimes referred to as 'superfast broadband'. Fiber-optic, due to it's lower attenuation, can provide vastly superior download and upload speeds; when compared to copper and mobile broadband networks. Fiber-optic networks have been laid in the UK by Virgin Media and BT; alongside a few regional providers. Fiber-optic cabling has been implemented in a range of configurations: Fibre To The Home / Premises (FTTH/FTTP); Fibre To The Cabinet (FTTC); and Fibre To The Building (FTTB). FTTH provides the highest data download speed because it comes directly into the home, the downside is that it is the most expensive to implement. The other configurations (FTTC / FTTB) rely on a combination of fiber and copper, and therefore it is not as powerful as FTTH (due to the copper entering the home on the final 'leg' of the connection).

bullet Pro and Cons

You may have been wondering what a fibre optic network is and how it applies to broadband. Currently the majority of UK broadband subscribers connect via the UK copper landline telephone network. Landline connection is sometimes described as an electrical connection. Fibre optic cable differs to an electrical connection. Instead a light is transmitted across optical fiber. These pulses of light have a big advantage over the standard electrical connection. Listed below are the advantages of fibre optic (when compared to copper / dsl):

  1. Higher bandwidth. Meaning you can download alot more data faster.
  2. Less data loss over distance. (up to sixty miles, compared to one or two for copper)
  3. Less cross talk.
  4. Simplicity. One fibre optic cable can do the work of countless electric links.
  5. Fibre cable is cheaper than copper cable.

The disadvantages of fibre optic are as follows:

  1. Currently access packages are more expensive than DSL alternatives.
  2. Less functional, a copper wire can transmit data and power outputs.
  3. Fibre optic cables can be problematic to splice and can fuse.
  4. Not needed for low bandwidth activities due to it's cost of implementation.
  5. While fibre cable is cheaper than copper it's expensive to build a whole new network.

To achieve super fast broadband (download speeds of 50mb plus) fibre optic networks are the only option. Copper networks are not capable of providing the bandwidth necessary for tomorrow's digital technologies. Virgin media implemented the UK's first fibre optic network for broadband users. With a download speed of 50mb, it was the fastest broadband service available to UK users; before 2011. BT launched their own fibre optic access in 2011; they are currently calling it BT Infinity. Ofcom have stated (2015) that the majority of the UK's fibre optic infrastructure has been implemented by Virgin Media and BT. Early issues with fiber optic services was access and cost: it was only available to 8.3 million Britons by 2012, and due to the fairly high costs of installing a nationwide fibre optic network, access packages were not cheap (prior to 2014). It is doubtful whether rural area's will have access to super fast fibre optic broadband in the near future - although the UK Government has set a universal goal of 10 mbit/s by 2020.