Sunday, June 23, 2024

Riding The LASER Wave

By Commander Rahul Verma  

The idea of using light as a weapon can be traced back to the ancient Greek scientist Archimedes, who lived in the third century BC. According to Lucian, a writer, Archimedes destroyed enemy ships using mirrors that collaborated as parabolic reflectors to focus the sun’s rays and set the ships on fire. This use of light as a weapon may have been the first recorded example of what would eventually become laser technology. Fast forward to the twentieth century, the laser has become a key technology contributing to major world economy sectors. French physicist Louis des Brailles once said, “The laser has a great future. It is difficult to predict where and how it will find its application, but I think that it is a whole new age of technology.” In the last few decades, lasers have moved from “a solution looking for a problem” to the leading technology in mechanisms that achieve indispensable roles in numerous other activities, including transportation, healthcare, and telecommunications. 

However, lasers are not just limited to being a valuable tool in civilian life. They have also become an effective weapon system. In today’s digital age, speed and security are two of the most critical aspects of communication, particularly in the defence industry. As threats to national security become increasingly erudite, the need for protected and dependable communication channels is more imperative than ever. One technology that promises to meet these requirements is laser communication. Laser stands for ‘Light Amplification by Stimulated Emission of Radiation’, a cutting-edge technology that uses light to transmit information over long distances at high speeds. 

The battlefield requires advanced technology capable of detecting targets at great distances and exchanging vast amounts of information rapidly and securely. Lasers have revolutionised warfare, serving as accessories to high-energy weapons and offering a variety of other applications, including battlefield illumination, rangefinding, target designation, LIDAR (Light Detection and Ranging), communication, power beaming, and active remote sensing. Laser systems provide broadband capacity links with Swap benefits due to their high frequency and extraordinary angular resolution, making them perfect for tactical deployment. Laser devices are also used when anti-jamming is essential or when the RF spectrum is inaccessible. 

Space, the final frontier, is also where the laser is proving its mettle. The use of lasers in space has become increasingly important due to the numerous objects in orbit around the Earth. These objects move at high velocities and pose a significant threat to space assets. In addition, a collision between these objects can trigger a chain reaction that can cause extensive damage to active satellites. The risk of space debris is not limited to natural occurrences; space warfare is also a growing concern. Laser technology has been developed to address these challenges for early warning detection and protection of space assets. This technology employs electronically controlled antennas to track detected objects and search for others simultaneously. Because of this, laser technology is now proving to be an effective tool for space asset protection, and it is gaining traction as a solution for both natural and human-made threats. With this kind of innovation, tracking and identifying micro-debris is now possible, too. 

114 AI is an Indian Institute of Technology (IIT) Delhi-based Indian startup working on space domain awareness (SDA) that has deployed and integrated some of its products. They are also actively involved with the United States Air Force (USAF), US Space Force, US Air Force Research Laboratory (AFRL), and the United Kingdom’s Defence Science and Technology Laboratory (DSTL). They are also working with General Atomics Aeronautical Systems (GA-ASI) on next-generation optical artificial intelligence (AI) technology.  

To exploit a laser as a directed energy weapon (DEW), it requires a large amount of power, computed in megawatts (MW), to inflict substantial damage on the intended target. However, many engineering challenges still need to be tackled to compensate for beam wandering caused by environmental factors such as bad weather conditions, target movement, or platform motion. Additionally, high-energy lasers (HELs) pose a substantial hazard to sensors and military equipment on the battlefield, which may require a protection mechanism, such as a laser jamming feature, to ensure the reliability and integrity of this equipment in a hostile electromagnetic warfare setting. In the realm of cyber warfare, game-changing technologies such as quantum computing and cryptography have emerged, providing a potential safeguard for tactical communication against eavesdroppers. These technologies may offer an added layer of protection against cyber threats and enhance the security of sensitive information. 

With all this ongoing development and current capacities, it’s a surety that laser technologies will dominate battle space in the future. With high energy comes the need for technological leaps and other input from microelectronics organisations. With this futuristic need for maintaining military superiority in the region, Naval Innovation and Indigenisation Organisation (NIIO) and Technology Development and Acceleration Cell (TDAC) created Challenges for homegrown Indian startups. Semiconductors are crucial in this flight to self-reliance as they are a critical component in this architecture. One of the industry innovation partners of NIIO, 3rdiTech is one of the first Indian semiconductor companies to design these kinds of sensors and chips. They are also effectively creating a complementary metal-oxide semiconductor (CMOS) chip and laser-based optical fuse.  

Atmanirbhar Baharat at the chip-level

Laser communication has found several use cases in the defence industry, one of the most noteworthy being satellite communication (SATCOM). Laser technology offers higher data transmission rates between satellites and ground stations than traditional radio communication, allowing for real-time transmission of more data, such as high-resolution images and videos. Another potential application of laser communication is in unmanned aerial vehicles (UAVs). By utilising laser communication, UAVs can provide commanders with up-to-date information on the battlefield in real-time. Laser communication technology also has the potential use in tactical communication systems to provide soldiers with secure and reliable communication channels.

What do deep space exploration and underwater work have in common? Quite a bit. Laser communication can be used for air-to-underwater and submarine-to-submarine communication and in satellite and tactical communication systems. The limitations of traditional communication methods, such as radio and acoustic signals in underwater environments, are due to sound waves being absorbed and scattered. However, laser communication can overcome these limitations by utilising light to transmit information. The underwater telephone (UWT) is a standard communication system across navies worldwide and is microprocessor controlled. It enables communication between surface/subsurface vessels by using underwater acoustic waves. 

Utilising either the upper or lower sideband, along with a suppressed carrier frequency, ensures a  high signal-to-noise ratio and transmission bandwidth. However, this method suffers from the low bandwidth of ~ Kilohertz (kHz), the low data rate of ~ kilobits per second (kb/s), as well as high latency caused by the low speed of underwater acoustic waves, multipath propagation, and Doppler spread. Underwater wireless communication is vital for oceanography research, offshore oil exploration, and seafloor monitoring, and upgrading this outdated technology has significant military advantage along with high commercial potential. 

The sea remains one of the few remaining unexplored frontiers, but, in many ways, we still need to get past the paddling in the shallows stage. An example of this challenge is in the field of communication, where maintaining contact with submersibles and unmanned underwater vehicles can be difficult. The issue arises from the fact that water is hostile to electromagnetic communications. Considering this aspect, as part of the Innovations for Defence Excellence (iDEX) Supporting Pole-Vaulting in R&D through Innovations for Defence Excellence (SPRINT) Challenge, two problem statements were released: effective underwater communication to operate without compromising stealth. Also, underwater detection and ranging for mission-critical dunked and airborne applications. The most viable solution was from XD Defence Systems. They are an Indian defence sector startup founded as part of an Atmanirbhar Bharat-inspired opportunity, having a range of laser-based products from anti-drone applications to communication to environmental monitoring.  

Laser weapon systems have undergone rapid development in recent times, with dedicated research and development (R&D) significantly advancing the state-of-the-art. What was once inconceivable a couple of decades ago has now become a reality. Major General August Schomburg, who was the head of the US Army Ordnance Missile Command, wrote a letter in 1962, “I feel as do others here that the laser may be the biggest breakthrough in the weapons area since the atomic bomb.” This perspective was widespread among military personnel during the early stages after the invention of the laser. As per a recent evaluation published by one of the world-renowned think tanks, every air force, army, or navy around the world is involved in or planning to initiate some form of fundamental or applied research or experimental development related to lasers and optical systems. Therefore, the laser’s ability to establish fast and reliable communication could significantly transform the operations of unmanned underwater vehicles (UUVs).

Cdr. Rahul Verma is presently posted at TDAC looking after Unmanned Systems and Aviation Innovations. He is a Seaking Pilot with 4,000 flying hours experience. The officer is also a qualified RPA crew with an extensive experience in unmanned flying operations. He holds a Masters degree in Aerospace Law and a Post Graduate Diploma in Autonomous Systems and Product management. He is also pursuing MBA from Washington University and IIT-Bombay

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