14 DAY TRIAL // Scientists at the Aston University, in the United Kingdom, can boast, at this point, having control over the longest fiber laser in the world. Their physics device was created from, and now occupies more than 270 kilometers (168 miles) of optical fiber cable. The science group at the university believes that the new instrument could provide other scientists with a totally different perspective on the emerging fields of information transmission and secure communications, AlphaGalileo reports.
Telecommunications and broadband access are among the main research goals of the British team and are also one of the main reasons why it has been conducting investigations into optic fiber lasers. One of the main lines of research today is the creation of new methods of converting electrical impulses into light, and then sending them through such a fiber cable. At this point, existing technologies rely on using transmission amplifiers along the cable. This is necessary because the signal loses about five percent of its clarity and power for every kilometer it travels. But the amplification also has negative side-effects, such as distorting the original input signal, and making it noisier.
The UK team believes that a cavity in the optical fiber system may be just the needed thing to eliminate the amplifiers from the scheme. It says that it can now use the Raman effect – a natural physical phenomenon that affects all light passing through various materials – and Bragg gratings to make the signal stronger and clearer over significant distances. A Bragg grating is basically a reflector constructed in a short segment of the optical fiber that is able to only reflect particular wavelengths of light, while transmitting all of the others.
This is not the first time the Aston University group engages in fiber optics lasers. It is also the holder of the previous world record, which was set in 2006. That achievement saw the creation of a 75-kilometer-long fiber laser. Now, the team managed by AU Photonics Research team Professor Sergei Turitsyn has succeeded in exceeding its own performance several times over. Details of the new Ultralong Raman Fiber Laser appear in a recent issue of the respected scientific journal Physical Review Letters.
“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. However, even more interesting is a fundamentally new way the laser is used – as a transmission medium, rather than a source of coherent radiation,” Turitsyn explains.
“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 fiber 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,” he adds. Researchers from the Instituto de Optica, in Madrid, Spain, and the Institute of Automation and Electrometry, in Novosibirsk, Russia, also participated in the work.