A ‘record-breaking’ development in laser technology from the University of Glasgow could help support the development of smaller, cheaper, more easily-fabricated optical and quantum technologies, its inventors say.

Researchers from Glasgow’s James Watt School of Engineering have designed and built a narrow-linewidth laser on a single, fully integrated microchip that has achieved the best performance ever recorded in semiconductor lasers of its type.

The team’s new system, which they call a ‘topological interface state extended laser with optical injection locking’, or MOIL-TISE, is capable of producing a narrower, purer laser light than any previous distributed feedback (DFB) laser system.

While previous high spectral purity lasers faced balancing top-level performance with compact design, often resulting in hybrid integration and bulky external components, which limited their practicality, the MOIL-TISE system has been developed on a single integrated chip.

The system uses a uniquely-shaped design, which breaks the chip into three regions, each with its own optical phase, specifically tuned to keep the light evenly distributed between them.

Combined with a device called a micro-ring resonator integrated into the chip, the system can internally recycle light to stabilise its performance and enable the system’s tightly-focused linewidth.

Its creators claim that the new laser could help overcome many of these barriers that prevented previous generations of this type of monolithic semiconductor laser technology from being more widely adopted, and allow for applications in emerging technologies such as advanced communication systems and quantum cryptography.

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Researchers said that the new laser is capable of easily switching between optical phases, a property required in quantum key distribution systems, which could underpin the unbreakable encryption and communication devices of the future.

“The University of Glasgow is unique in the UK in that it’s possible to take a project like this from an initial idea to a fully-featured prototype without leaving our campus,” said Dr. Xiao Sun, one of the project’s leads from Glasgow University’s Critical Technologies Accelerator.

“This research represents a great example of the kind of breakthroughs that the Critical Technologies Accelerator is working to make. 

“Being able to fabricate this at the James Watt Nanofabrication Centre using technology which is commercially available shows that industry could easily start to make their own MOIL-TISE-based devices easily and affordably in the years to come.”

The team’s paper, Narrow-linewidth monolithic topological interface state extended laser with optical injection locking, is published in Science Advances.