PIB TrackerJNCASR silicon chip carries 100 Gbit/s terahertz past barrier
JNCASR researchers used topological photonics in a silicon chip to send terahertz signals across an engineered barrier at up to 100 Gbit/s with only 1-2% loss, a step toward compact circuits for 6G.
What happened
- JNCASR, an autonomous institute of the Department of Science and Technology, reports a silicon chip that lets terahertz waves pass through an engineered barrier with little loss while carrying data at up to 100 Gbit/s.
- The chip uses topological photonics: triangular holes in a silicon slab form a photonic crystal that mimics graphene's honeycomb lattice, and the barrier is made by changing hole sizes over a short section.
- A single barrier added about 1-2% loss and two in sequence about 2-3%, while a conventional waveguide barrier markedly reduces transmission.
- Three devices were tested across 310-360 GHz: a double-barrier guide at 48 Gbit/s, an omega-shaped route with four sharp bends at 60 Gbit/s, and a power splitter at 100 Gbit/s using QAM-32.
- The study, led by Dr Abhishek Kumar and published in Advanced Materials, plans to tune the barriers electrically, thermally or mechanically so a device can redirect signals.
For Prelims
- Terahertz band: roughly 0.1 to 10 THz, between microwaves and infrared; the tests used 310-360 GHz, the lower edge of the band.
- 6G and IMT-2030: the ITU's framework for sixth-generation systems is IMT-2030, with commercial use expected around 2030; India's Bharat 6G Alliance works toward it (PIB 2321533).
- Bharat 6G Vision: released in March 2023, it set India's goal to design, develop and deploy 6G; the Alliance of industry, academia and Government followed in July 2023.
- Topological photonics: borrows from topological phases of matter (Nobel Prize in Physics, 2016) to make light follow edge channels that resist backscattering from defects.
- Klein tunnelling: named after Oskar Klein (1929), it describes a relativistic particle crossing a high barrier with little reflection; the figure caption calls this photonic Klein tunnelling.
- QAM: quadrature amplitude modulation encodes bits in a signal's amplitude and phase; QAM-32 carries 5 bits per symbol.
- Gbit/s versus GB: 100 Gbit/s is 12.5 gigabytes a second, so the release's 5-gigabyte film needs about 0.4 seconds in principle.
- JNCASR: an autonomous institute under the Department of Science and Technology, Bengaluru, founded in 1989; high-resistivity silicon suits established semiconductor fabrication.
For UPSC: JNCASR (DST autonomous institute) silicon photonic crystal: terahertz data at 100 Gbit/s across a barrier, 1-2% loss; 310-360 GHz tests; QAM-32 splitter; published in Advanced Materials.
What it is NOT: The release does not say when a chip like this could reach a commercial 6G network or what it would cost to make. The tests were passive devices on a bench: no transmitter, receiver or antenna integration is described. It gives no figures for loss over longer routes or for many barriers, and nothing on temperature or manufacturing variation. It names no industry partner or patent, and it does not say whether the work was funded under a specific DST programme.
For Mains
Syllabus: GS3.13 · GS3.12 · Linkage L1
Anchor
Wireless networks are moving to ever higher frequencies, and every step up makes signals harder to guide. A chip that tolerates bends and barriers addresses that directly.
Substantiation (data)
The JNCASR chip carried up to 100 Gbit/s across a barrier with about 1-2% loss for one and 2-3% for two, tested over 310-360 GHz in three silicon devices.
Position
The barrier is set by hole geometry, which gives designers a rule rather than a lucky result, and high-resistivity silicon fits existing fabrication lines.
Counterpoint
This is a laboratory result on passive circuits. Terahertz sources, detectors and antennas, and losses in air, remain open problems for a working 6G link, and no timeline is offered.
Way forward
Fund the tunable versions the team plans, link academic labs with the Bharat 6G Alliance and domestic fabs, and test the design inside full transmit-receive chains.
Conclusion
A neat step in guiding terahertz light. 6G needs the surrounding hardware to follow.
Deploys into: Indigenous telecom R&D and 6G · Basic research in India's autonomous institutes · International scientific collaboration · Semiconductor-compatible photonics
Ministry of Science & Technology · 2026-11-04 · PRID 2332613 · PIB source ↗