Photonics advance could enable compact, high-performance lidar sensors with no moving parts

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"... A new study from ... researchers could help to enable next-generation lidar sensors that are compact, durable, and have no moving parts. The key advance is a novel design for a silicon-photonics chip, which is a semiconductor device that manipulates light rather than electricity.  ...

To avoid these drawbacks, the ... researchers designed and demonstrated an array of integrated antennas that minimizes unwanted crosstalk between the antennas. Their innovation allows a lidar chip to scan a wider field of view while maintaining low-noise operation compared to other silicon-photonics-based approaches. ..."

From the abstract:

"Integrated optical phased arrays (OPAs) have emerged as a promising technology for many applications due to their ability to dynamically control free-space optical beams in a compact and non-mechanical manner.

However, these integrated OPAs typically have a restricted field of view (FOV), limited by grating lobes caused by large antenna pitches that are typically necessary to reduce crosstalk between the antennas in the integrated OPA.

In this work, we develop and experimentally demonstrate for the first time, to the best of our knowledge, a set of integrated grating-based antennas with significantly-reduced inter-antenna crosstalk that enable half-wavelength-pitch integrated OPAs with grating-lobe-free and wide-FOV functionality.

First, we derive a generalized theoretical model to describe the coupling dynamics between lossy modes in a system and use this model to analyze the coupling between antennas.

Next, we design and demonstrate a set of three integrated grating-based antennas with different propagation coefficients to enable reduced inter-antenna crosstalk, successfully measuring a significant reduction from 100% to 1% coupling.

Finally, using these reduced-crosstalk antennas, we develop and demonstrate a half-wavelength-pitch integrated OPA, successfully demonstrating grating-lobe-free and wide-FOV functionality.

This work facilitates new functionality for high-performance integrated OPAs."

Photonics advance could enable compact, high-performance lidar sensors | MIT News | Massachusetts Institute of Technology "With a novel design, MIT researchers overcame a stubborn problem that has limited the effectiveness of chip-based systems for lidar."

Reduced-crosstalk antennas for grating-lobe-free and wide-field-of-view integrated optical phased arrays (open access)

Fig. 1: Wide-FOV integrated-OPA concept.

Fig. 2: Design of reduced-crosstalk antennas.

Jelena Notaros, senior author (Source)