A research team led by the Indian Institute of Technology Guwahati (IIT Guwahati) has developed a free-space optical communication system for information transfer. In free-space communication, an IIT Guwahati statement says, data in the form of voice, text or image is transmitted using light wirelessly rather than through optical fibres and it represents the next generation of communications technology.
The research team was led by IIT Guwahati faculty, Bosanta Ranjan Boruah, Department of Physics, IIT Guwahati; and Dr Santanu Konwar, Assistant Professor at the Department of Physics, Abhayapuri College, Assam. The results of this pathbreaking work have recently been published in “Communications Physics” a highly reputed journal belonging to Nature Publishing Group.
Explaining the technicality of the research, Dr Boruah said: “In our work, the transmission station modulates the phase profile of a laser beam that carries the data, in terms of the strengths of a few Zernike modes. In the process, we also enhance the information content per modulation cycle of the laser beam.”
The research team has demonstrated the distortion-free transmission of text messages and images over a distance of one kilometre even in the presence of turbulence during stormy weather. The communication system can be used for high speed and secured communication between two individuals located either inside a building or outside.
In this communication system, the statement says, a unique mechanism has been implemented that can compensate for the effect of atmospheric turbulence so that the user information can be transmitted even through turbulent atmosphere resulting in negligible error at the receiving station. The transmission is directed strictly towards the receiver, unlike other wireless forms of communication in which the information is transmitted in all directions, adding to the security of the communication, the statement added.
“In addition to eliminating errors in communication, our system is also insulated from hacking and interloping, because the receiver decodes the transmitted beam by measuring the phase and not the power of the light beam, with prior knowledge about the strength and types of Zernike modes used, which make it more secure than wired and other conventional wireless forms of communication”, added Dr Konwar.
