Scientists at the Harvard School of Engineering and Applied Sciences have developed the first fully integrated high-power laser on a lithium niobate chip. The study is published in the journal Optica.

A team of engineers led by professor of electrical engineering and applied physics Marko Lončar used small but powerful lasers with distributed feedback for their integrated chip.

The researchers combined a laser with a 50 GHz lithium niobate electro-optical modulator to create a powerful transmitter of up to 60 mW in waveguides. The lasers are placed in small depressions engraved on the surface of the modulator plate.

Long-distance telecommunications networks, data center optical connections, and microwave photonic systems use lasers as the basis for data transmission. In most cases, as the researchers note, lasers are devices external to the modulators. Such a distributed system is more expensive and less stable than an integrated one. In addition, it is more difficult to scale.

Integrated thin-film photonics based on lithium niobate is a promising direction for the implementation of high-performance optical systems at the chip scale, the scientists note. It is already actively used in the work of many modulators, frequency combs and frequency converters. However, so far it has not been possible to create a laser on a chip.

“In this study, we applied all the nanofabrication techniques and techniques used in previous developments in the field of integrated lithium niobate photonics to overcome these problems and integrate a high-power laser into a thin-film lithium niobate platform,” says Prof. Lonchar.

The integration of thin-film devices and high-power lasers, engineers believe, opens the door to high-power, low-cost, high-performance transmitters and optical networks. The technology enables the development of powerful telecommunications systems, fully integrated spectrometers and efficient frequency converters for quantum networks.

“The integration of high-performance lasers will significantly reduce the cost, complexity and power consumption of future communication systems,” said Amirhassan Shams-Ansari, co-author of the study. “It’s a brick that can be integrated into larger multi-directional optical systems such as sensors, lidars, and telecommunications networks.”

Scientists will continue to work to increase the power of the laser and the possibilities for its application in other areas.