CHENNAI: On November 12, when the rest of the country was busy celebrating the festival of lights, one professor and a bunch of PhD students of IIT Madras were toiling in the laboratory to light up a 4x4 silicon photonic processor chip.
They successfully attached a fibre optical array to the silicon photonics integrated circuits, paving the way for the processing of optical signals for data transmission and computing. This process would make the photons or light encode and decode data carried through electrons to overcome bandwidth limitations.
Silicon photonics chips are similar to electronic chips but they use light instead of electrons. Usually, silicon photonic chips are integrated with electronics with optics technologies in a single package to provide a wide range of functions. It can process both electronic and optical signals.
The electronic integrated circuits or chips are used in literally everything from cars to smartphones to light bulbs. The size of the chips has come down to nanometres, but it has physical limitations.
“Silicon photonics came up because of limitations in the electronics industry. Whenever your tech node or transistor size is coming down, on-chip copper wire and transistors are densely packed. They interfere with each other causing interconnect bottlenecks," said Professor Bijoy Krishna Das, chief investigator at Centre for Programmable Photonic Integrated Circuits and Systems (CPPICS), IITMadras. This affects data transmission speed and power consumption, among other things, he added.
Silicon photonics are crucial for high-performance computing, and high-speed data transmission in data centres and telecommunication areas. Fibre array attachment is achieved for the first time in the country, he said. "Though the technology is mainstream in data centres, only a handful of companies know the technology. They provide an unparalleled cheaper and energy efficient system for high-speed and long-haul data transmission, 5G, 6G telecommunication."
The centre is focusing on the development of silicon photonic device prototypes for data centres and telecommunication equipment such as beamformers and microwave filters for 5G and 6G communication. It is also involved in emerging technologies such as quantum computing. “Photons are quitbs or quantum bits(the fundamental block in quantum computing). We're working on silicon photonic devices for quantum processing and quantum key distribution (secure communication),” he said.
The research centre is collaborating with some of the leading semiconductor firms, startups, and foundries. The centre aims to be self-sufficient in research and look at revenue potential from licensing intellectual property for devices, joint development of technology with private players, R&D service for startups, and others.
Professor Bijoy Krishna Das started working with Silicon Photonics back in the 1990s when it was just a research idea among academics. After pursuing his research at IIT Kharagpur and later in Germany, he wanted to carry out the research in India. He wanted to establish a research centre on silicon photonics at IIT Madras in 2006. However, his fellow academics who were working abroad thought India was not ready for such cutting-edge research. The lack of fabrication, research funding, and the lack of an academic ecosystem posed huge challenges.
However, a small opto-electronics lab with `5 lakh seed money was established in 2006 at IIT Madras. It has been an uphill battle since then. Now the facility has Rs 46.20 crore research funding for the 2021-2026 period, which is a huge sum considering the standards in India. CPPICS was funded by Meity, IIT MadrasIoE, and private players.
Unlike the old days, the centre now has the capacity to design, fabricate, package, and test chips, making it a complete ecosystem for research. TNIE visited these facilities after Diwali day. It also taps into the rich integrated chip-designing talent pool from IIT Madras faculty. The increasing number of doctoral students in the centre also boosted its position.
Applications of silicon photonics circuits, which include quantum computing, are considered critical technologies for national security and could be used as military weapons or as a geo-political tool via sanctions. The latest round of crackdown on Chinese firms is around LiDAR technology, over concerns of its military application.
Having missed the electronic revolution bus, India is now trying to catch up in semiconductor manufacturing capabilities. Technocrats and economists are unanimous that the country must build on education, research, and innovation even as it is focused on improving its manufacturing capabilities.
What are silicon photonics? Where is it used?
⦁ Silicon photonics are crucial for high-performance computing, and high-speed data transmission in data centres. It has already adopted in data centre equipment
⦁ Wider bandwidth requirements of 5G & 6G telecom need silicon photonics.
⦁ These critical as more people deploy large artificial intelligence, machine learning systems
⦁ Autonomous vehicle players using Lidar (light detection and ranging) to measure distance, and read traffic signals are also increasingly looking into silicon photonic chips
Market forecast (2021- 2027)
⦁ Overall market to jump from $152 mn in 2021 to $970 mn in 2027 at 36% CAGR
⦁ Data centre transceivers from $148 mn to $468 mn
⦁ 5G transceivers from $0.6 mn to $2.2 mn
⦁ Consumer health applications market to grow $240 mn
⦁ Co-packaged engines market to grow $7.2 mn
⦁ Automotive LiDAR market to grow to $1.5 mn
(Source: Yole Research, Courtesy: CPPICS)