A research team led by IIT Guwahati has developed a novel free-space optical communication system for information transfer.
As per a statement by IIT-G, the team of researchers was led by Bosanta Ranjan Boruah, a faculty member of physics at IIT Guwahati, and Santanu Konwar, an assistant professor at the department of physics, Abhayapuri College.
Meanwhile, free-space communication systems developed all over the world so far use a type of light beam called the vortex beam to encode the data. The problem is the use of vortex beam is that it can be distorted by turbulence that may occur in the medium of propagation. Data transmitted wirelessly using light/laser beams can become corrupted when transmitted through atmospheric turbulence such as wind.
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.
Bosanta Ranjan 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.”
As per report by Santanu Konwar, “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.”
The research team has demonstrated the distortion-free transmission of text messages and images over distance of one kilometre even in the presence of turbulence such as during stormy weather.