What Is Silicon Photonics?
Traditional silicon chips use electrons to carry data; silicon photonics replaces them with photons (light particles).
Photons move data faster, with more capacity and less energy loss.
Used in data centres, sensors, and quantum computing.
Big challenge: integrating the light source (laser) directly onto the silicon chip.
The New Breakthrough
Scientists grew mini-lasers directly on silicon wafers, solving a long-standing problem.
They used standard complementary metal-oxide-semiconductor (CMOS) chip-making techniques, meaning the method fits well into existing factories.
This makes the tech scalable, cheaper, and faster.
How the Laser Works
A laser amplifies light by exciting electrons to release photons.
Silicon can't efficiently emit light due to its atomic structure (indirect band gap).
Gallium arsenide can emit light well (direct band gap) but is hard to combine with silicon due to crystal mismatches.
Solution: grow gallium arsenide in tiny trenches on the silicon wafer, so defects are trapped and don’t affect the laser.
How the Chip Was Made
Built on a 300 mm silicon wafer (industry standard).
Lasers made with layers of indium gallium arsenide for light, and indium gallium phosphide for protection.
300 working lasers were made on one wafer.
Light travels in nanometre-scale ridges (waveguides) on the chip.
Requires very low power (only 5 mA) and runs well at room temperature.
Why This Matters
Enables faster, more efficient communication between chips in computers.
Could cut energy use in data centres.
A step closer to mass-producing photonic chips.
Still needs improvement to work better at higher temperatures.
COMMENTS