Exploring New Ways To Control Light On Photonic Chips

Modern society increasingly relies on optical systems that control and measure light for applications such as fast wireless communication, safe autonomous vehicles, and high-quality biomedical imaging. However, many of these systems depend on large lenses, moving components, or complex instruments, making them difficult to miniaturize, scale up, and operate at high speeds. In his PhD research, Zhiyu Chen explores how optical functions can be implemented on photonic chips to overcome these limitations. Photonic chips guide and process light in much the same way that electronic chips process electrical signals.

Zhiyu Chen examines the potential of photonic chips by first focusing on controlling light through disordered media such as biological tissue. When light travels through these media, it becomes distorted. Correcting this distortion can help deliver light to a desired position, which is useful for biomedical imaging, as well as for communication and sensing applications in complex environments. In his research, Chen used a photonic chip based on indium phosphide to control light through disordered media at high speed. This system operates much faster than conventional technologies and includes on-chip optical amplifiers that increase the available output power.

Disorder as a useful tool
Chen also investigated how disorder, which is often considered undesirable in optical systems, can be turned into a useful tool. He developed a specially designed disordered surface for use with an integrated optical phased array. This array can rapidly steer a light beam without the need for moving parts. The proposed method allows light to be steered across a wider range of angles and enables the system to distinguish between more closely spaced angles, contributing to the development of more compact LiDAR and optical communication systems.

Compact and affordable spectrometers
In addition, Chen integrated a compact disordered region into a silicon photonic chip to create an on-chip spectrometer for analyzing the spectrum of light. The disordered region improved the spectrometer’s ability to distinguish between closely spaced wavelengths. The system requires only a single detector, reducing both cost and complexity. This approach could lead to compact and affordable spectrometers for environmental monitoring, industrial sensing, agriculture, and healthcare.

Overall, this research demonstrates that combining photonic chips with disordered structures can provide new ways to control and analyze light. The results contribute to the development of faster, smaller, and more versatile optical systems for future communication, imaging, and sensing applications.

This research was supported by PhotonDelta and the China Scholarship Council.