Microwave photonics chip uses optics for analog computation

A research team led by Professor Wang Cheng from the Department of Electrical Engineering (EE) at City University of Hong Kong (CityUHK) has developed a world-leading microwave photonic chip that is capable of performing ultrafast analog electronic signal processing and computation using optics.

Researchers from City University of Hong Kong (City UHK) have developed a microwave photonic chip that is capable of performing ultra-fast analog electronic signal processing and computation using optics. The chip, which is reportedly 1000 times faster and consumes less energy than a traditional electronic processor, has a range of applications in areas such as 5/6G wireless communication systems, high-resolution radar systems, artificial intelligence, computer vision and image/video processing.

The research findings have been published in the scientific journal Nature. The expansion of wireless networks, the Internet of Things and cloud-based services has placed significant demands on underlying radio frequency systems. Microwave photonics (MWP) technology, which uses optical components for microwave signal generation, transmission and manipulation, offers solutions to these challenges. However, integrated MWP systems struggle to achieve ultrahigh speed analog signal processing with chip-scale integration, high fidelity and low power simultaneously.

Professor Wang Cheng from CityUHK said the researchers developed an MWP system that combines ultrafast electro-optic (EO) conversion with low-loss, multifunctional signal processing on a single integrated chip. This was achieved by using an integrated MWP processing engine based on a thin-film lithium niobate (LN) platform capable of performing multi-purpose processing and computation tasks of analog signals.

The team has been researching the integrated LN photonic platform for years; in 2018, the researchers developed a CMOS (complementary metal-oxide semiconductor)-compatible integrated electro-optic modulator on the LN platform, which laid the foundation for the current research. LN is referred to as the “silicon of photonics” for its importance to photonics comparable to silicon in microelectronics.

Feng Hanke, first author of the paper, said the chip can perform high-speed analog computation with ultrabroad processing bandwidths of 67 GHz and enhanced computation accuracies. This research opens up a new research field (LN microwave photonics) that could facilitate the development of microwave photonics chips with compact sizes, high signal fidelity and low latency.

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