Fibre optics are delivering data speeds of 1Tbps, and the theoretical limit for current technologies used on fibre are as high as 25Tbps, says Tim Smith, Nbase Xyplex fibre guru.
He says the next step for fibre networks will be optical add/drop multiplexer (OADM) networks, which route and switch fibre without the relatively slow intervention of electronics. Through fibre switching, wavelength switching and wavelength conversion, the possibility of a fibre-only network emerges, boasting speeds that will put its copper brethren to shame.
The increase in speed without loss of distance is due to dense wave division multiplexing (DWDM), which uses single-mode fibre - fibre capable of carrying one beam of light, as opposed to multi-mode fibre, which can carry many beams at once, but is limited to distances shorter than 100km.
Instead of pushing more beams down the pipe, the light is split into different colours, allowing multiple beams to travel down the line at once without interfering with one another.
The system was fuelled by organisations with a need to increase bandwidth on existing fibre infrastructures, termed fibre mining. The two solutions that emerged were full duplex and wave division multiplexing.
Full duplex involves transmitting and receiving over the same pipe, effectively doubling fibre capacity while saving on installation and upgrade costs. The other solution - WDM - initially offered two or more wavelengths per strand. Coarse WDM pushed the limits to four, and then all the way to eight. DWDM is defined as over eight channels, and is believed to be the bandwidth-killer of the future - and the present.
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