Frequency-Modulated Continuous Wave Technology Is the Future of LidarFrequency-Modulated Continuous Wave Technology Is the Future of Lidar
Frequency-Modulated Continuous Wave (FMCW) technology gives lidar the ability to measure velocity and see through weather.
October 18, 2023
Sometimes technology advances through wholesale change, like when cellular phone networks switched from analog to digital signals, and sometimes there is incremental change, like when CD players switched from using red lasers to using blue ones to increase the available resolution for movies on Blu-ray discs.
The latter is the case for frequency-modulated continuous wave lidar, which provides an incremental advance over traditional lidar by tweaking the way it measures the signal from the laser.
Most lidar measures the laser signal’s time of flight to measure things like location and distance, but FMCW lidar works more like radar, measuring the Doppler shift of the signal’s frequency to also gather velocity data, reports Adam Carter, CEO of photonic application specific integrated circuit (PASIC) supplier OpenLight.
In addition to adding the measurement of targets’ speed, FMCW lidar also has a longer range and it cuts more effectively through fog, mist, and rain, letting the lidar work better in all weather. The longer range is possible because the FMCW signal is transmitted coherently and received coherently explained Carter. “This allows you to go farther,” he said. In addition, FMCW lidar is unaffected by glare from the sun or interference from other lidars.
OpenLight was formed in 2022 by partners Synopsis and Juniper Networks to commercialize integrated silicon photonics technology first developed in 2008 by Aurrion, a University of California, Santa Barbara spin-out company acquired by Juniper in 2016.
The obstacle, as it usually is for technology advances, is cost. “Today it is very expensive with the conventional technology that is available,” Carter noted. “If you didn’t integrate [onto a single chip], you’d have to have discrete components and all that optical coupling,” he pointed out.
OpenLight’s solution is to offer semiconductors with integrated lasers (photonic integrated circuits) that can apply the benefits of large-scale semiconductor fabrication to the problem of connecting lasers with processors. “With our revolutionary integration of lasers and electro-absorption modulators, 2xFR4 PASIC epitomizes our dedication to simplifying complexity, reducing costs, and setting new standards in efficiency,” he said.
OpenLight relies on Tower Semiconductor for the actual fabrication work letting customers use the 2xFR4 PASIC validated reference design to build products without having to design, engineer, and test their own solutions.
Because this is all in silicon, Moore’s Law is at work, promising improvements in the future. “The real beauty of this system is you can shrink it,” Carter said. “The 16 channels enable a better pixel refresh rate, and because it is silicon you can repeat that and go up to 32 channels in the future to get better clarity.”
At the Munich motor show, lidar manufacturer Aeva displayed its Aeries II lidar product that will employ OpenLight’s PASIC to deliver what the company describes as “4D lidar.” Aeva claims the following benefits for Aeries II:
Long Range Performance: Detect, classify, and track dynamic objects such as vehicles, cyclists, and pedestrians at long distances.
Ultra Resolution: A real-time camera-level image that provides up to 20 times the resolution of conventional 3D lidar sensors.
Road Hazard Detection: Spot small objects on the roadway with greater confidence at up to twice the distance of conventional 3D lidar sensors.
4D Localization: Estimate vehicle motion in real-time with six degrees of freedom for accurate positioning and navigation without the need for additional sensors, like IMU or GPS.
“Lidar is very close to being like a radar system,” said Carter. “You’ll see lidar evolve in the same way,” he predicted.
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