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MIT researchers developing LiDAR on a chip

Researchers at MIT’s Photonic Microsystems Group are developing a LiDAR-on-a-chip system that is smaller than a dime, has no moving parts, and could be mass produced at a very low cost to be used in self-driving cars, drones, and robots. An article describing the new system is published in IEEE Spectrum.

Most LiDAR systems—like the ones commonly seen on autonomous vehicles—use discrete free-space optical components like lasers, lenses, and external receivers. In order to have a useful field of view, this laser/receiver module is mechanically spun around, often while being oscillated up and down. This mechanical apparatus limits the scan rate of the LiDAR system while increasing both size and complexity, leading to concerns about long-term reliability, especially in harsh environments. Today, commercially available high-end LiDAR systems can range from $1,000 to upwards of $70,000, which can limit their applications where cost must be minimized.

Applications such as autonomous vehicles and robotics heavily depend on LiDAR, and an expensive LiDAR module is a major obstacle to their use in commercial products. Our work at MIT’s Photonic Microsystems Group is trying to take these large, expensive, mechanical LiDAR systems and integrate them on a microchip that can be mass produced in commercial CMOS foundries.

Our LiDAR chips promise to be orders of magnitude smaller, lighter, and cheaper than LiDAR systems available on the market today. They also have the potential to be much more robust because of the lack of moving parts, with a non-mechanical beam steering 1,000 times faster than what is currently achieved in mechanical LiDAR systems.

—Christopher V. Poulton and Michael R. Watts

The device is a 0.5 mm x 6 mm silicon photonic chip with steerable transmitting and receiving phased arrays and on-chip germanium photodetectors. The laser itself is not integrated into the chips; however, there are on-chip lasers that could be integrated in the future.

In the current version of the LiDAR chip, thermal phase shifters directly heat waveguides through which the laser propagates. Silicon’s index of refraction—which changes the speed and phase of light passing through it—depends on its temperature. As the laser passes through the waveguide, it encounters a notch fabricated in the silicon, which acts as an antenna, scattering the light out of the waveguide and into free space. Each antenna has its own emission pattern, and where all of the emission patterns constructively interfere, a focused beam is created without a need for lenses.

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A scanning electron microscope image of MIT’s solid-state lidar. The device uses thermal phase shifters to heat the waveguides through which the laser propagates, changing the speed and phase of the light that passes through them. Notches fabricated in the silicon act as antennas, scattering the light into free space, and constructive interference is used to focus the beam without a need for lenses. Poulton and Watts. Click to enlarge.

The current on-chip LiDAR system can detect objects at ranges of up to 2 meters; the researchers are hoping to achieve a 10-meter range within a year. They said there is a clear development path towards technology that can reach 100 meters, with the possibility of going even farther.

The MIT team is producing the LiDAR chips on 300-millimeter wafers, making their potential production cost on the order of $10 each at production volumes of millions of units per year.

Comments

HarveyD

Excellent news. This could be a major step for much lower cost LIDARs for future ADVs.

Alain

Could it also be used to detect, identify (with low power) and shoot down ("high" power) mosquitoes?

Enough power to damage their wings is enough.

Could be integrated in the galaxy S9

HarveyD

Manufacturers of anti-malaria, anti-dengue and anti-sika, doctors, hospitals and associates would not like those Lidars at all.

Many Asian and African countries would be overpopulated in less than 50 years.

MaartenV

With a $10 production cost we are looking at a $100 device price. About the same as Quanergy hopes to ask for their offering.

Good to have competition. I think we really need lidar for full autonomous cars.

P.S.
And the only antidote to overpopulation is educating women.

Account Deleted

Maarten you can drive a car and you do not have lidar eyes but simple video sight so we don’t need lider for fully autonomous cars. Science teams like lidar because its resolution is low (meaning less data input) and it works natively in 3D (meaning you do not need complex software to make dual cameras make a 3D image) and it work just as good with or without daylight. Camera sensors can do the same with the right software, more computing power and light sensitive sensors. Camera sensors will always cost less and have much more range and better resolution than lidar.

I think radar will see more use in fully autonomous cars as they can see in heavy rain and fog which cameras and Lidar cannot. You could drive at full speed in heavy rain or fog without risk with a high resolution radar which would be valuable for taxi services and fully autonomous semis that need to operate as many hours as possible during the year.

PS a laser mosquito killer will definitely use 3D cameras as Lidar does not have the resolution to see and recognize a mosquito.

HarveyD

What would be the potential total side effects of some 240,000,000 Lidars and other radar and laser sensors in operation in USA, specially on pedestrians in large cities?

Arnold

H.D.
Similar to supermarket checkouts, mobile phones or satellites.

Similar to much low power E.M.F.
noise.

The science usually refers us back to the (small?) emitted intensity relative to background natural emissions. Mitigated or reduced by the distance from source.

The relevance of selected frequency band interacting with the object of interest vis insects, eyes, brain, skin etc or other electrical devices operating on or susceptible to interference at those frequencies.

We are totally reliant on good science and proper regulation in todays world.

Google 'city 40'



HarveyD

'reliance on good science and proper regulation' is well said.

However, the majority suffers with 100s (if not 1000s) man made sicknesses for which we have not produced effective vaccines. Corrective medicine is more profitable?

USA with 19+ % invested into corrective medicine is more and more obese and sick. Rising pollution and higher GHG will make it worse by 2050+. Life expectancy has not moved much in the last 30+ years.

Highly concentrated low power active sensors + phones + play gadgets etc may eventually have long term side effects on users and bystanders? Time will tell?

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