MIT researchers have developed a novel silicon-photonics lidar sensor designed to provide a compact, durable alternative to traditional bulky lidar systems while expanding the device’s field of view and maintaining high precision. The innovation addresses longstanding challenges in beam steering for autonomous navigation and other applications.
Lidar sensors use pulses of infrared light to measure distances and create high-resolution three-dimensional maps of environments. Conventional lidar units rely on mechanical parts that rotate to scan their surroundings, making them large, expensive, and prone to wear. Silicon-photonics-based lidar systems instead steer light beams electronically through integrated optical phased arrays (OPAs), eliminating moving components.
A critical limitation of existing silicon-photonics-based OPAs has been their restricted field of view, partly caused by interference when light-emitting antennas are placed too close together. To prevent signal jamming or crosstalk, antennas have traditionally been spaced farther apart, which leads to multiple unwanted light beams (grating lobes) that reduce precision and waste power.
The MIT team overcame this by designing three types of antennas with different geometries and propagation properties within the same array. This approach minimizes crosstalk despite closer spacing, enabling a wider scanning range without degrading beam quality. Each antenna emits light uniformly at coordinated angles, ensuring coherent beam steering without the false signals typically caused by grating lobes.
Lead author Henry Crawford-Eng and senior author Jelena Notaros, a professor of electrical engineering and computer science at MIT, demonstrated an optical phased array with about 1% coupling between antennas, a significant improvement over the 100% coupling seen in conventional designs. This resulted in a single, precise beam capable of scanning over a broader field of view.
The findings were published in Nature Communications and represent an important technical step toward chip-scale lidar systems suitable for autonomous vehicles, aerial surveying, and construction monitoring. The researchers plan to expand the field of view further and explore new design options based on their electromagnetic coupling theory.
Why it matters
Advancements in integrated optical phased arrays can make lidar systems smaller, more reliable, and more cost-effective, facilitating wider adoption in autonomous vehicles and other robotic applications that require precise environmental sensing without bulky moving parts. The MIT innovation addresses key barriers in current lidar technology by improving scanning range and accuracy while reducing noise and power loss.
Background
Traditional lidar systems use rotating mechanical parts to direct laser pulses around a 3D scene, but these mechanisms increase size, cost, and maintenance needs. Silicon photonics offers a solid-state alternative by manipulating light on a semiconductor chip using integrated antennas in optical phased arrays. However, interference between closely spaced antennas limits steering angle and quality, constraining practical lens-free scanning.
By altering antenna geometry and managing light propagation with rigorous electromagnetic design, MIT’s approach mitigates crosstalk effects, allowing denser antenna arrays that produce cleaner, wider angle beams without mechanical motion. This represents a foundational improvement in semiconductor-based lidar sensor technology.
Sources
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