Researchers in Switzerland have developed a technique that improves control over the wavelength and polarisation of lasers used in optical communications.
It is claimed the development, from a team from EPFL and the Swiss Federal Laboratories for Materials Science and Technology (EMPA), opens new frontiers in basic research and could help future expansion of the internet because it improves the signal transmitted down fibre-optic cables.
To obtain the right wavelength, the EPFL researchers adapted the lasers’ size.
In parallel, the EMPA scientists designed a nanometre-scale grating for the emitter in order to control the light’s polarisation.
They were able to achieve this feat by vaporising long molecules containing gold atoms with a straw-like tool operating above the lasers.
Using an electron microscope, they were able to arrange and attach gold particles to the surface of each laser very precisely. Once deposited, the grating serves as a filter for polarising the light.
This technique is claimed to facilitate a high-speed throughput of several gigabits per second with reduced transmission errors.
‘This progress is very satisfying,’ said Eli Kapon, head of EPFL’s Laboratory of Physics of Nanostructures. ‘These kinds of lasers are also useful for studying and detecting gases using spectroscopic methods. We will thus make gains in precision by improving detector sensitivity.’