S. Vishnu Sharma
IIT Guwahati is in the news once again for achieving another great thing.
A team of researchers led by IIT Guwahati faculty Dr. Bosanta Ranjan Boruah and Dr. Santanu Konwar developed a novel free-space optical communication system for information transfer.
Dr. Bosanta Ranjan Boruah is a faculty with department of physics at IIT Guwahati. And Dr. Santanu Konwar is assistant professor at Department of Physics at Abhayapuri College in Assam.
In free-space communication, 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 results of this pathbreaking work by IIT Guwahati faculty and team of other researchers has recently been published in “Communications Physics (https://www.nature.com/articles/s42005-020-00468-1)” a highly reputed journal belonging to Nature Publishing Group.
IIT Guwahati scientists develop great optical communication system
The past couple of decades have seen phenomenal developments in free-space communication.
Most free-space communication systems developed so far all over the world use a type of light beam called the vortex beam to encode the data.
The problem in the use of a vortex beam is that it can be distorted by turbulence that may occur in the medium of propagation.
In effect, data transmitted wirelessly using light/laser beams, can become corrupted when transmitted through atmospheric turbulence such as wind.
To overcome this problem, the IIT Guwahati researchers have, for the first time, used orthogonal spatial light modes called Zernike modes to encode the data and to transmit the same robustly in the form of the phase profile of a laser beam.
Explaining the technicality of the research, Dr. Bosanta Ranjan Boruah of IIT Guwahati said in their 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, he said.
At the point of reception, the laser beam with encoded user information is sensed by a specially designed wavefront sensor that decodes the user information.
In this communication system, 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, says Dr. Boruah of IIT Guwahati.
Dr. Santanu Konwar says 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, he said.
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Furthermore, 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, says the researcher.
The research team comprising IIT Guwahati faculty and team of other researchers demonstrated the distortion-free transmission of text messages and images over a distance of one kilometre even in the presence of turbulence such as during a stormy weather.
The communication system can thus be used for high speed and secured communication between two individuals located either inside a building or outside.
About IIT GuwahatiIIT Guwahati established in 1994 has completed 25 years of glorious existence in 2019.
At present, the Institute has eleven departments and five interdisciplinary academic centres covering all the major engineering, science and humanities disciplines, offering BTech, BDes, MA, MDes, MTech, MSc and PhD programmes.
IIT Guwahati offers a residential campus to 412 faculty members and more than 6,000 students at present.
Besides its laurels in teaching and research, IIT Guwahati has been able to fulfil the aspirations of people of the North East region to a great extent since its inception in 1994.
The picturesque campus is on a sprawling 285 hectares plot on the north bank of the Brahmaputra, around 20 kms from the heart of the Guwahati city.