Novel Photonic Chip Bridges Digital and Analog

JOEL WILLIAMS, ASSOCIATE EDITOR
joel.williams@photonics.com

Researchers from George Washington University (GWU) and UCLA developed and demonstrated a photonic digital-to-analog converter without leaving the optical domain. The technology has the potential to advance next-generation data-processing hardware, with implications for data centers, 6G networks, and AI, among others.

GWU associate professor Volker J. Sorger and his colleagues used a silicon photonic chip platform to create a digital-to-analog converter (DAC) that does not require the signal to be converted into the electrical domain.

“We realized that there is a fundamental disconnect between electrical signals being digital, and optical information processing, which is analog,” Sorger told Photonics Media. “Thus a digital-to-analog converter is needed that especially does not require an optical-electrical-optical transduction.” Eliminating optical-electrical-optical conversion improves the DAC, and therefore overall system performance, he said.

DACs, Sorger said, are part of an enabling technology that has contributed greatly to the digital revolution; the technology is used in mobile phones, smart speakers, communication systems, and a number of other applications. In the case of a smart speaker, digital signals, such as those from a smartphone playing music, must be converted into sound. This is an analog signal.

The optical technology allows for a seamless integration of photonics into electrical systems, which is critical to 5G and the upcoming 6G. Data centers, Sorger said, are using more and more photonic technologies for network-edge computing such as taking in data from a sensor and processing it directly in the optical analog domain.

Part of the attraction of photonic technologies lies in the high bandwidth of optical signals, and more recently, Sorger said, the opportunities to accelerate mathematical functions optically, such as in neural networks and machine learning. The technology is in especially high demand with Industry 4.0. Each of those applications requires high-performance DAC converters.

The researchers intend expand on the system by increasing the bit-resolution system. They are also seeking partners to transition the technology to, Sorger said.

The research was published in Advanced Photonics Research (www.doi.org/10.1002/adpr.202000033).