MIT engineers cut antenna-to-antenna interference on a silicon-photonics lidar chip from roughly 100 percent to about 1 percent, while steering one clean beam across a wide field of view. The result, published July 22, 2026 in Nature Communications, tackles the central trade-off that has kept chip-based lidar narrow-sighted: dense antenna spacing for a wide view versus spacing for low crosstalk.

The chip relies on an integrated optical phased array, or OPA — no rotating parts, no motors to wear out. Conventional lidar spins a bulky unit to sweep infrared pulses across a scene. An OPA instead steers the beam electronically by shifting the phase of light fed to each antenna on the chip.

Why did antenna spacing cap the field of view?

Antennas placed close together couple. They scramble each other's light. Engineers traditionally fixed this by spacing antennas farther apart, but wide spacing spawns grating lobes — unwanted copies of the main beam at different angles. The sensor can only steer its primary beam so far before it drowns in those copies, which also waste energy and trigger false detections.

"This limits our field of view, so the autonomous vehicle now only knows what is in front of it for a certain angular range," says Andres Garcia Coleto, an EECS graduate student at MIT and co-author on the paper.

What did the MIT team change?

In a standard OPA, every antenna carries the same corrugation pattern, so neighbors interact strongly. The MIT team, led by Robert J. Shillman Career Development Associate Professor Jelena Notaros, replaced the identical antennas with a repeating set of three antennas, each with a distinct shape. They varied antenna width along with the size and placement of the corrugations. Different geometry means a different propagation coefficient — how light moves through each structure.

"Because the antennas have very different propagation coefficients, when we put them close together, essentially each antenna doesn't 'see' the antenna next to it. Therefore, it won't couple with its neighbor," Garcia Coleto says.

That solved half the problem. The other half: differently shaped antennas tend to behave differently, and the array needed every antenna to emit identically. The team set three requirements:

• Each antenna emits the same amount of light.
• Each releases its beam at the same angle for a given wavelength.
• The emission angle changes evenly across the array as the beam steers.

"We have this challenge where we require the antennas to have different geometries to reduce the crosstalk, but we need to simultaneously design the antennas to have the same emission characteristics," says lead author Henry Crawford-Eng, an EECS graduate student. "While it is possible to engineer this, it is extremely difficult."

The researchers first worked out the electromagnetic theory of how radiative modes couple, then used that framework to drive design and simulation before fabricating the OPA — some of the work done at MIT.nano. Under the test conditions, a conventional OPA of the same spacing would have coupled at roughly 100 percent. The MIT design hit about 1 percent, steered the beam across a broad field of view, and produced no grating lobes at all.

What does it mean for lidar makers?

Silicon-photonics lidar promises sensors far smaller and cheaper than mechanical units, with the durability that comes from no moving parts — attractive for autonomous vehicles, drones, aerial mapping, and construction-site monitoring. The catch has always been the narrow field of view near scene edges, and the noise that earlier widening attempts introduced.

"The functionality we demonstrated in this work solves a fundamental problem for integrated optical-phased-array technology, enabling future lidar sensors that can achieve significantly higher performance than we could demonstrate previously," Notaros says.

Joyce Poon, professor of electrical and computer engineering at the University of Toronto and director of the Max Planck Institute of Microstructure Physics, who wasn't involved in the work, called the antenna design "an important step forward for chip-scale, solid-state beam-steering technology."

The research drew support from the Semiconductor Research Corporation, the National Science Foundation, a MIT MathWorks Fellowship, the U.S. Department of War, and the MIT Rolf G. Locher Endowed Fellowship. The team next plans to refine the method for an even broader viewing range, and is exploring a second wide-field-of-view approach that surfaced while developing the underlying theory — work that will decide whether OPA lidar can match the scanning envelope mechanical systems deliver today.