New Chip Revolutionizes Signal Processing and Computation

A research group headed by Professor Wang Cheng of City University of Hong Kong's (CityUHK) Department of Electrical Engineering (EE) has created a cutting-edge microwave photonic device that can process analog electronic signals and compute using optics at ultrafast speeds.

The chip has a wide range of applications, encompassing 5G and 6G wireless communication systems, high-resolution radar systems, artificial intelligence, computer vision, and image/video processing. It is 1,000 times quicker and uses less energy than a standard electrical processor.

The research was published in the journal Nature. The study was conducted with The Chinese University of Hong Kong (CUHK).

Due to the Internet of Things, cloud-based applications, and wireless networks growing so quickly, there are now a lot more demands on underlying radio frequency systems. Effective answers to these problems can be found in microwave photonics (MWP) technology, which generates, transmits, and manipulates microwave signals using optical components.

Nevertheless, chip-scale integration, low power consumption, high fidelity, and ultrahigh-speed analog signal processing have proven difficult for integrated MWP systems to accomplish simultaneously.

To address these challenges, our team developed an MWP system that combines ultrafast electro-optic (EO) conversion with low-loss, multifunctional signal processing on a single integrated chip, which has not been achieved before.

Benshan Wang, Professor, Study Corresponding Author, Chinese University of Hong Kong

An integrated MWP processing engine built on a thin-film lithium niobate (LN) platform that can handle multipurpose processing and analog signal computing duties facilitates this performance.

The chip can perform high-speed analog computation with ultrabroad processing bandwidths of 67  GHz and excellent computation accuracies.

 Feng Hanke, Ph.D. Student and Study First Author, Chinese University of Hong Kong

The group has been committed to studying the integrated LN photonic platform for several years. The recent scientific accomplishment was made possible by the development of the world's first integrated electro-optic modulators on the LN platform compatible with CMOS (Complementary Metal-Oxide Semiconductor) in 2018 by colleagues at Nokia Bell laboratories and Harvard University.

Due to its significance to photonics, similar to that of silicon in microelectronics, LN is known as the “silicon of photonics.”

Their study provides a chip-scale analog electrical processing and computing engine and opens up a new research field, namely LN microwave photonics, enabling microwave photonics chips with tiny sizes, excellent signal quality, and low latency.

The paper's first authors are Feng Hanke and Ge Tong, both EE undergraduates. Professor Wang is the corresponding author. Additional contributors comprise Dr Guo Xiaoqing, a Ph.D. Graduate in EE; Dr. Chen Zhaoxi, Dr. Zhang Ke, and Dr. Zhu Sha, who are also affiliated with Beijing University of Technology, as well as Dr. Sun Wenzhao, currently at CityUHK (Dongguan), all of whom are EE postdocs.

Zhang Yiwen, an EE Ph.D. student, also contributed to the study. Collaborators from CUHK include Wang Benshan, Professor Huang Chaoran, and Professor Yuan Yixuan.

Journal Reference:

‌Feng, H., et al. (2024) Integrated lithium niobate microwave photonic processing engine. Nature. doi.org/10.1038/s41586-024-07078-9