Laser focusses on lithium niobate chip

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Researchers have developed the first fully integrated high-power laser on a lithium niobate chip, an advance that could lead to less expensive, more stable and scalable optical carriers used in data transmission.

lithium niobate chip
The on-chip laser is combined with a 50GHz electro-optic modulator in lithium niobate to build a high-power transmitter. (Credit: Second Bay Studios/Harvard SEAS)

The development from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), working with industry collaborators Freedom Photonics and HyperLight Corporation, is detailed in Optica.

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“Integrated lithium niobate photonics is a promising platform for the development of high-performance chip-scale optical systems, but getting a laser onto a lithium niobate chip has proved to be one of the biggest design challenges,” said Marko Loncar, the Tiantsai Lin Professor of Electrical Engineering and Applied Physics at SEAS and senior author of the study. “In this research, we used all the nano-fabrication tricks and techniques learned from previous developments in integrated lithium niobate photonics to overcome those challenges and achieve the goal of integrating a high-powered laser on a thin-film lithium niobate platform.”

According to SEAS, Loncar and his team used small but powerful distributed feedback lasers for their integrated chip. On chip, the lasers sit in small wells etched into the lithium niobate and deliver up to 60mW of optical power in the waveguides fabricated in the same platform. The researchers combined the laser with a 50GHz electro-optic modulator in lithium niobate to build a high-power transmitter.

“Integrating high-performance plug-and-play lasers would significantly reduce the cost, complexity, and power consumption of future communication systems,” said Amirhassan Shams-Ansari, a graduate student at SEAS and first author of the study. “It’s a building block that can be integrated into larger optical systems for a range of applications, in sensing, lidar, and data telecommunications.”

By combining thin-film lithium niobate devices with high-power lasers using an industry-friendly process, this research is claimed to represent a key step towards large-scale, low-cost, and high-performance transmitter arrays and optical networks. Next, the team aims to increase the laser’s power and scalability for more applications.