February 15, 2023: Just over two years after their  pathbreaking innovations in the technology of  transmitting digital data wirelessly in the form of light pulses was sealed with three global patents, IIT Guwahati  Physics Professor  Bosanta Ranjan Boruah and his PhD student  Santanu Kanwar, now   an Assistant Professor, teaching  Physics in Abhayapuri College in Assam,  have achieved an important landmark:
Unlike so much of academic work that remains within the covers of doctoral theses,  the  novel “ Free Space Optical Communication System”  (FSO) developed by the duo  has been  technology-transferred to a private sector Indian company who is arguably the leading provider of optical  wireless solutions.
A release from IIT Guwahati,  has announced that  the transfer of technology has been completed to  Ahmedabad-based Nav Wireless Technologies, which has hitherto exploited another optical communication technology – LiFi or light-based WiFi. 
We spoke to both co-developers of the technology  to understand why this made-in-India solution  claims to innovate in a  communications arena that has been around  for a decade or more and is being tried in many countries.
They explained that simply put, FSO  replaces  physical   data communication channels like fibre optic cable  with  an optical system, where data is converted into optical pulses  representing ones and zeroes and transmitted  wirelessly to a receiver  where  an optical receiver unscrambles the  pulses and reconverts it back into digital data.  Such systems can send and receive data at very high speeds – around 1.25- 1.5 gigabits per second – and the IIT Guwahati researches have achieved  distances of up to 1 km, in a lab set up.
This can – and presumably will – be scalable to larger distances by the tech partner, Nav Wireless Technologies.
Dr Kanwar explained that the  patents earned by the work. (The  16-page US patent can be read here)  spell out how their system overcomes the main obstacles to uninterrupted FSO communication,  weather conditions like fog.  He added: “Our system is highly secure and it requires multiple keys to decode the data… there is no possibility of unauthorised interception.”
This suggests why world-wide military agencies  including the US Defence Advanced Research  Projects Agency (DARPA, have been among the earliest to embrace  free space optical communication.   
The  pluses of the IIT Guwahati technology --  enhanced security features and the ability to overcome severe atmospherics, would make it an ideal for India’s armed forces along  the  northern and north-eastern borders where  low visibility and fog/snow are perennial challenges
The only requirement is that  multiple towers, within a few kilometers of   within each other’s  line of sight are required to bounce the optical signals across the terrain. The other  option tried by some military users is to bounce the signal off satellites.
In the civilian sector too,  the FSO  solution when rolled out commercially will help  provide secure and high-speed  data communications  for enterprise customers.
Says Prof Boruah: “Free space optical communication is likely to play a crucial role in the coming days both in case of indoor applications and outdoor especially in the defence sector. We will be looking forward to meet the challenges as our technology is adapted to serve the society.
Adds Hardik Soni,  Nav wireless Technologies’ CTO & Co-Founder: “NavTech is a  pioneer in India doing research on Optical Wireless technologies  developing applications, and manufacturing LiFi and  FSO products & solutions. We are glad to join hands with one of India’s premier technology institutions for further development of Optical Wireless technology.”
The work of these Assam-based researchers  will hopefully  result in the coming months in   the rollout of robust systems that will ensure Indian ownership  and control over  mission -critical communication technology  for both civilian and defence applications.

For illustrations see Image of the Day