Researchers have developed the first fully integrated high-performance laser on a lithium niobate chip, an advance that could lead to cheaper, more stable and scalable optical carriers used in data transfer.
The development of the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with industrial collaborators Freedom Photonics and HyperLight Corporation, is described in detail in optics†
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“Integrated lithium niobate photonics is a promising platform for developing high-performance chip-scale optical systems, but getting a laser on a lithium niobate chip has proven 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 nanofabrication tricks and techniques learned from previous advances in integrated lithium niobate photonics to overcome those challenges and achieve the goal of integrating a high-power laser on a thin-film lithium niobate platform.”
According to SEAS, Loncar and his team used small but powerful lasers with distributed feedback for their integrated chip. On the chip, the lasers sit in tiny pits etched into the lithium niobate and deliver up to 60 mW of optical power into the waveguides fabricated in the same platform. The researchers combined the laser with a 50GHz electro-optical modulator in lithium niobate to build a powerful transmitter.
“Integrating powerful plug-and-play lasers would significantly reduce the cost, complexity and power consumption of future communications systems,” said Amirhassan Shams-Ansari, a SEAS graduate student and first author of the study. “It is 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 an important step towards large-scale, low-cost, high-performance transmitter arrays and optical networks. Next, the team plans to increase the laser’s power and scalability for more applications.