Laser communications

Academics at Aston University in Birmingham, UK have invented the world’s longest laser. They have transformed an optical fibre 75 kilometres long into the laser, which the team hopes will improve long distance transmissions across the World.

The new laser is special because it can transmit light signals over such a long distance without any loss of power, so the signal that is being sent barely deteriorates. When normal telephone conversations or data sent over the internet are converted to light in order to travel through standard optical fibres the signals lose around five per cent of their power for every kilometre that they travel. The signals then have to be amplified to ensure that they reach their destination. But any time the signals get amplified, the background noise gets amplified too, until it gets so high the signals can not be understood anymore.

Now Dr Juan Diego Ania Castañón and his colleagues at Aston University have used a special process called the Raman effect (a natural phenomenon that affects light passing through a material) to transform a long optical fibre into an ultra-long laser.