‘First’ integrated laser to emit high-coherence light at telecoms wavelengths

25 Oct 2022

University of Rochester says its narrow linewidth source “could reshape landscape of integrated photonics”.

A research team co-led by Qiang Lin, a professor of electrical and computer engineering at the University of Rochester, NY, USA, developed the first multi-wavelength integrated laser to achieve the following:

• Emit high-coherence light at telecommunication wavelengths;
• Allow laser-frequency tuning at record speeds; and is
• The first narrow linewidth laser with fast configurability in the visible waveband.

The project, described in Nature Communications, was co-led by John Bowers, distinguished professor at University of California Santa Barbara (UCSB), and Kerry Vahala, professor at the California Institute of Technology. Lin Zhu, professor at Clemson University, also collaborated on the project.

The technology “has the potential to reshape the landscape of integrated photonics,” write co-lead authors Mingxiao Li, a former PhD student in Lin’s Laboratory for Nanophotonics at Rochester’s Hajim School of Engineering & Applied Sciences, and Lin Chang, a former postdoc at UCSB.

The developrs say that the new source “will pave the way for new applications of integrated semiconductor lasers in lidar remote sensing that is used, for example, in self-driving cars”. The technology could also lead to advances in microwave photonics, atomic physics, and AR/VR, they add.

Chip laser solution

Integrated semiconductor lasers have been at the core of integrated photonics, enabling many advances over the last few decades in information technologies and basic science.

“However, despite these impressive achievements, key functions are missing in current integrated lasers,” commented Li.

“Two major challenges, the lack of fast reconfigurability and the narrow spectral window, have become major bottlenecks that stall the progression of many evolving applications,” added Chang.

The researchers say they have overcome these challenges by creating a new type of integrated semiconductor laser, based on the Pockels effect. The laser is integrated with a lithium-niobate-on-insulator platform.

They comment that the new technology includes these beneficial features:

• Fast frequency chirping, which will be invaluable in lidar sensor systems, which measure distance by recording the time between emission of a short pulse and reception of reflected light.
• Frequency conversion capabilities that overcome spectral bandwidth limitations of traditional integrated semiconductor lasers. This will “significantly relieve” the difficulties in developing new wavelength lasers, says the team; and
• Narrow wavelength and fast reconfigurability, providing a “fully on-chip laser solution” to probe and manipulate atoms and ions in atomic physics, and benefit AR/VR and other applications at short wavelengths.