
MIT and DARPA Pack Lidar Sensor onto Single Chip - Osiris30
http://spectrum.ieee.org/tech-talk/semiconductors/optoelectronics/mit-lidar-on-a-chip
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mstresh
I believe that LIDAR will be to silicon photonics what the accelerometer was
to MEMS.

The real challenge that the article only touched upon is to get lasers into
the same package and keep the costs down. This is still an active area of
pursuit in both research and industry--though, there are several promising
methods emerging. The $10 cost used in the article is likely closer to the
cost of the bare silicon die. Packaging is always the expensive part of optics
(doubly so if the lasers are not monolithically or heterogeneously integrated
onto the same die). That being said, even with today's technology, integrating
a laser chip and a silicon photonics chip into a package is easily south of
$1k, which is what they quoted competing technologies costing.

I look forward to seeing these sensors integrated into my self-driving car in
5-10 years.

~~~
azernik
From this part of the article, the team seems fairly confident in their
ability to integrate the laser onto the same die as the waveguides. This seems
very plausible to me, given how standard this integration is in communications
applications (eg fiber optic transceivers)

> Our 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 part of these particular chips, but
> our group and others have demonstrated on-chip lasers that can be integrated
> in the future.

~~~
mstresh
The Watts group at MIT has done some fantastic work into rare-earth doped
silicon waveguides to produce lasers on a silicon platform [0]. However, I
believe this work is still very much in the research stage. I'm not convinced
their method is scalable to production for this $10 & million-unit-per-year
LIDAR application since Erbium-doped waveguide lasers still require an off-
chip pump laser source.

[0] (PDF):
[http://www.rle.mit.edu/pmg/documents/OpticsExpress2014Bradle...](http://www.rle.mit.edu/pmg/documents/OpticsExpress2014Bradley.pdf)

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calebm
For those curious about performance: "At the moment, our on-chip lidar system
can detect objects at ranges of up to 2 meters, though we hope to achieve a
10-meter range within a year. The minimum range is around 5 centimeters. We
have demonstrated centimeter longitudinal resolution and expect 3-cm lateral
resolution at 2 meters. There is a clear development path towards lidar on a
chip technology that can reach 100 meters, with the possibility of going even
farther."

~~~
Aelinsaar
So we have LIDAR on chip, and RADAR on chip. All while there is a revolution
in machine learning.

OK, I'm excited.

~~~
dharma1
What's the radar on chip?

~~~
fudged71
Google's sensor for future watch UIs

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skoocda
This is incredible work. The low price point should create and burgeoning open
source / hacker dev community, which in turn, will hopefully greatly
accelerate 3D perception algorithms.

My recent EE capstone project was in the area of autonomous vehicle SLAM
perception and control- but we were limited by cost to using a PrimeSense
Kinect for 3D perception, which had pretty lacklustre resolution. This chip-
based LiDAR would have been warmly welcomed at the time. Regardless, I'm glad
I'll be able to revamp the project when these hit the market! The more
sensors, the better!

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iandanforth
A similar technology that is much closer to market:

[http://spectrum.ieee.org/cars-that-
think/transportation/sens...](http://spectrum.ieee.org/cars-that-
think/transportation/sensors/quanergy-solid-state-lidar)

------
TYPE_FASTER
Solid state lidar is here: [http://www.quanergy.com](http://www.quanergy.com)

They were talking $250 per unit for volume pricing.

~~~
TaylorAlexander
Quanergy has yet to ship any production units. They've also been delaying for
years. I have no doubt that they are building solid state lidar, but their
tech isn't really "here" yet.

~~~
Animats
I was wondering what happened to those guys. They announced another new model,
but haven't shipped the first one yet. As of May 2016, they were talking 2017.
Quanergy calls itself "The leading provider of LiDAR sensors" without having
shipped a product. Bad sign.

It's definitely possible, because ASC has been shipping such devices for
years, but at a much higher price point. Somebody is going to get this right
soon, but maybe not Quanergy. Those spinning Velodyne things have got to go.
Too clunky, and too expensive.

~~~
captaindiego
They've got a normal lidar unit they are shipping or at least offering dev
kits for now (similar to velodyne puck at a lower price point and less
scanning lines). So they are at least doing something in terms of real
products.

From what I've managed to gather from poking around a bit, I'd guess they're
using a very fancy waveguide based sensor similar to this, but a more simple
emitter as a way to save cost on their first generation solid state product.

I've heard also 2017 as well... but also would be curious to see any actual
progress.

~~~
TaylorAlexander
We had one of the mechanical Quanergy sensors at my last job, and I worked on
integrating it with ROS and doing some mapping with it. It was slow, not well
constructed (it kind of vibrated when rotating), and didn't return intensity
information (though it's possible a software update could change that).

At $8000 (later dropped to ~$5600), it was poor value. I've never used a
velodyne, but I looked over the marketing materials for the VLP-16 puck and it
seems like a much more well thought out product. This makes sense as Quanergy
is only selling mechanical LIDARs as a bridge, but the fact remains that they
aren't very good.

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azinman2
I have a lidar question that maybe HN can answer. So this work is super cool
and in the future I'm sure we'll have lots of lidar-based devices driving
around. But if we do, won't they interfere with each other and thus render the
lidars very inaccurate?

~~~
Animats
There are easy ways to protect a LIDAR against that, but I don't think
Velodyne is doing them yet. The duty cycle is low; a ranging operation takes
under 1us, and typical cycle rates are 100Hz. So each beam is live only about
1/10,000the of the time. A simple denial jammer thus needs far more power than
the pulsed laser used for ranging. A simple denial jammer looks like a target
at zero range, so you know you're being jammed. Note that jamming must the
same color as the ranging laser; everybody has narrow-band interference
filters that only pass a very narrow color band. That's why this works in
sunlight.

To defeat a synchronous jammer, the LIDAR only needs to add some random
variation in the transmit timing. Then the jammer won't know when to be on.
With some random variation, synchronous jamming looks like noise, rather than
a solid false reading.

This new MIT system requires that the received light be in phase with the
laser beam at the light coherency level. That makes it reasonably immune to
anything other than a laser that can sync to a narrow light pulse. Not sure
that's even possible.

~~~
drewm1980
Even if each ranging operation is fast, they will be scanning it around, so I
suspect the effective duty cycle will be higher. Light bounces all over the
place, so two sensors could still interfer even if they are measuring two
different paths in space. It can probably be resolved with careful, expensive,
and coordinated engineering, but I would expect the first gen sensors to
interfere with each other just as primesense cameras do unless the authors
explicitly claim otherwise.

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BatFastard
Would this work for doing hand position sensing?

I love LeapMotion for VR, blows touch controllers away, and this sounds even
better, smaller, faster, better resolution.

Hell we could have them in our sunglasses and it could map the world around us
as we walk. I want a shamanistic interface to D space!

~~~
empath75
Yeah, AR/VR was my first though.

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Sephr
How safe is it for our eyes if every single car on the road has multiple lidar
units running?

~~~
dharma1
Depends on the power and wavelength. 1400-2000nm is meant to be safer for
retina, not sure what these lidars use

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Animats
This is very nice. Phased-array beam steering on both transmit and receive,
and coherent detection to ignore any light that's not synced to the
transmitter. Now they have to get the range up. If they can get range up to
10m in the near term, that's enough for indoor navigation. That will be useful
for VR, AR, robot vacuum cleaners, and similar applications.

I've been expecting the Advanced Scientific Concepts flash LIDAR to be the
direction of the future, because it has no moving parts and works in sunlight
at range. It just costs too much. But this is potentially even better.

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dmritard96
always 'MIT ...'. their ability to brand is always amazing to me, otherwise
its usually 'researchers'

~~~
joelg
It's a feedback loop, and a very effective one. The stronger the brand is, the
more credibile your article will seem. The more credibile articles, the
stronger the brand becomes.

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doc_holliday
The application of these light phased arrays to Holography and the making of a
truly Holographic display with reasonable resolution is very exciting.

This is to Holographic displays as LEDs was to standard displays.

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chiph
Even if this doesn't have the range for autonomous vehicle hazard avoidance,
imagine it being used on regular cars for their blind-spot detectors. No more
false alarms on your radar detector.

~~~
jonknee
That will be a good first step. As well as better automated parking features.

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peter303
I saw a demo at SIGGRAPH last week with VR using helmet-LIDAR for model
building and geolocating. It was the $8K spinning LIDAR you see on Google
cars. Cant wait for the $100 version.

~~~
augustt
$8K LIDAR? From what I can find, it sounds like Google is using a $70K LIDAR.

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JoeAltmaier
Steerable? Could they create one that steers the laser emitters? And create a
no-moving-parts scanning projection screen?

~~~
neolefty
Yes, they do non-mechanical beam steering:

> 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.

The LIDAR chips don't use visible light, but the article talks about it as a
future project:

> We are also developing visible light phased arrays with applications such as
> Li-Fi and holography that can be seen by the human eye.

~~~
regularfry
It's a very simple, and very clever mechanism, too. My first guess was that
they were going to use piezo mechanisms to squish cavities, but heat is even
simpler.

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legulere
It looks like it's small enough to be included in a smartphone. That would be
pretty cool for crowdsourced streetview cartography like mapillary. Or 3D
scanning objects.

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logotype
My holy grail toy is a Velodyne LIDAR, but damn these things are expensive :(

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dharma1
awesome. Hope it won't take years to come to market

~~~
neolefty
It's still limited to use in the lab, or at least indoors, short-range:

> At the moment, our on-chip lidar system can detect objects at ranges of up
> to 2 meters, though we hope to achieve a 10-meter range within a year. The
> minimum range is around 5 centimeters. We have demonstrated centimeter
> longitudinal resolution and expect 3-cm lateral resolution at 2 meters.
> There is a clear development path towards lidar on a chip technology that
> can reach 100 meters, with the possibility of going even farther.

I wonder what the limiting factors are -- laser power, noise, calibration?

~~~
regularfry
That's immediately something that can be usefully put in a phone.

~~~
csours
What do you imagine being done with it? I'm thinking of lidar room mapping

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raverbashing
Tesla will be looking _very closely_ at these developments

Edit: Finding the downvotes funny. Certainly nobody remembers how other self-
driving cars are using LIDARs and what's the issue with current solutions

~~~
dharma1
Musk keeps saying radar+cameras is enough

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drcross
He's only saying that because of cost and size. If you could add this package
to a Tesla for 10 dollars per unit it would be stupid not to.

~~~
dharma1
I agree. Unless that meant admitting old sensors aren't good enough, and
recalling cars

