What enabled record-low visible-light loss on silicon chips?

Fiber-like photonics brings optical clarity to silicon

Engineers at Caltech have reworked on‑chip light pathways so silicon devices can guide visible wavelengths with losses previously achieved only in glass optical fiber. By shaping the photonic structures on silicon to behave like fibers—minimizing scattering and unwanted mode leakage—the team reduced visible‑light attenuation to a record low for silicon platforms. That lower loss means light circulating on a chip remains coherent for longer distances and times.

Why this matters

Lower optical loss on a silicon platform changes what integrated photonics can do. The immediate technical payoffs include:

• More coherent, low‑noise lasers integrated on chip, useful for precision measurement and communications.
• Improved quantum devices: reduced loss preserves fragile quantum states and lengthens interaction times for on‑chip quantum photonics and sensors.
• Smaller, energy‑efficient sensors and optical components because signals need less amplification and fewer loss‑mitigating elements.

Moving fiber performance onto silicon also matters for scale and manufacturing. Silicon fabrication is already the backbone of the semiconductor industry; bringing fiber‑like optical performance to that ecosystem promises faster translation from lab prototypes to mass‑produced devices. It lowers barriers for compact LIDAR, optical clocks, quantum sensors, and components for future quantum networks.

Remaining challenges

Integrating these low‑loss structures into full systems still requires work on coupling between chip and fiber, thermal stability, and packaging for real‑world environments. But by matching—or approaching—the performance of optical fiber while keeping the advantages of silicon manufacturing, the advance opens practical paths for more precise lasers, denser photonic integration, and next‑generation quantum and sensing technologies.