A 270km optical fibre has been
transformed into the world's longest laser, a feat its inventors believe will lead to a radical
new outlook on information transmission and secure communications.
at Aston University, UK, are leading research into ultralong fibre
lasers, to create a platform capable of delivering ‘next generation’
information transmission, including telecommunications and broadband.
telephone conversations or data sent over the internet are converted to light
in order to travel through standard optical fibres the signals lose around 5
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, a process
which creates background noise and affects the signals quality.
Using a physical
process called the Raman effect, a natural phenomenon that affects light
passing through a material and fibre Bragg gratings to reflect light at both
ends of the fibre, the team can create a uniform distribution of light through
a cavity in the optical fibre. This scheme also presents an ultra-long fibre
laser offering new opportunities for handling ultra-fast communications at a
high operational capacity.
Professor SergeiTuritsyn from Aston University’s Photonics Research team believes the 270km Ultralong
Raman Fibre Laser, (the result presented in a recent issue of Physical Review
Letters), has pushed laser technology to completely new territories. It
increases by a factor of three the Research team’s previous record result with
laser of 75km, reported in 2006.
The UK team have
been collaborating with the Instituto de Optica, Madrid, Spain and Institute
of Automation and Electrometry, Novosibirsk, Russia to achieve this record
“The demands on
communication systems are increasing significantly, particularly with the huge
growth of internet traffic. This technology offers a new platform for improving
the speed, reliability and the operational capacity of future optical
communication systems,” said Professor Turitsyn. “However, even more
interesting is a fundamentally new way the laser is used - as a transmission
medium, rather than a source of coherent radiation. Despite extraordinary
advances in laser science, only recently have the fundamental limits of laser
cavity length become an area of exploration. One important new concept
here is that an ultra-long laser cavity implemented in optical fibre can be
seen as a new unique type of a transmission medium. This might lead to a
radical new outlook on information transmission and secure communications.”