Indian-built silicon chip carries 100 Gbit/s terahertz signals past barriers, a step towards 6G

Researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) have built a silicon chip that carries terahertz signals past engineered obstacles with little loss, and sent data through it at up to 100 gigabits per second (Gbit/s), a step towards compact circuits for future 6G networks.

Sixth-generation networks are expected to use terahertz frequencies, which offer wide bandwidth. But bends, junctions and sudden changes in a waveguide scatter or reflect part of the signal, weakening it.

What the team did

The chip is a silicon photonic crystal, a slab with triangular holes in a pattern that mimics the honeycomb lattice of graphene. It guides terahertz waves along the boundary between two regions. The team created a barrier by changing the sizes of the holes over a short stretch.

A single barrier added only about 1–2% loss, and two barriers in sequence about 2–3%. In a conventional waveguide, the release says, a comparable barrier "markedly reduces transmission". The team says transmission stayed close to its barrier-free level while the barrier strength stayed below a characteristic coupling strength of the crystal, which gives a design rule.

The tests

Three devices were made on high-resistivity silicon, a material compatible with established semiconductor manufacturing, and tested across 310–360 GHz. Measurements agreed closely with simulations.

• Double-barrier device: 48 Gbit/s.
• Omega-shaped route with four sharp bends and a barrier: 60 Gbit/s.
• Power splitter with a barrier in one branch: 100 Gbit/s using QAM-32 modulation.

At 100 Gbit/s, the release says, a 5-gigabyte high-definition film could in principle be transferred in under half a second.

The study was led by Dr Abhishek Kumar of JNCASR, an autonomous institute of the Department of Science and Technology. The release describes laboratory demonstrations only and gives no timeline for 6G use.

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Source: official release by the Ministry of Science & Technology, issued through the Press Information Bureau, Government of India (04 NOV 2026 5:22PM by PIB Delhi). Read the full official text: Novel silicon chip allowing terahertz waves to pass through barriers could enable future 6G networks.