Wednesday, April 29, 2020

Apple iPad and Ouster LiDARs Compared

Ouster publishes an article "Why Apple chose digital lidar" by Raffi Mardirosian comparing its own design choices with Apple's. Few quotes:

"The iPad Pro is equipped with a Digital Flash Lidar (a type of solid-state lidar) system. As the name suggests, just like a camera’s flash, a flash lidar detects an object by emitting a light wall, instead of scanning the laser beam point by point in a traditional mechanical rotary lidar.

The system uses vertical cavity surface emitting lasers (VCSELs) paired with and single photon avalanche diodes (SPADs) for the light detectors, the same as with FaceID. These two technologies form the foundation of Digital Lidar and are ideally suited for commercialization for a number of reasons:
  1. VCSELs and SPADs offer a superior performance, form factor, and cost profile. VCSELs are smaller, lighter, more durable, and easier to manufacture compared with other emitter technologies. SPADs can be densely packed on a chip, count individual photons, and have excellent time resolution, resulting in a simpler, smaller, more durable, and natively digital architecture in contrast to legacy analog lidar detectors such as APDs or SiPMs (which could not fit in a consumer device).
  2. VCSELs and SPADs support a more rugged and robust system because they can both be integrated onto a chip. Printing all the lasers and all the detectors onto chips greatly reduces the number of components in the system and improves durability and ruggedness.
  3. VCSELs and SPADs have costs that fall faster with scale, are cheaper to produce in high-resolution implementations, and are improving along with Moore’s Law — whereas edge-emitting lasers and legacy analog APD and SiPM detectors are mature and have little room for improvement.
We are happy to see Apple come to the same conclusion that we did when we first designed our high-performance digital lidar sensors.

In fact, since we first designed our system in 2015, we’ve seen the performance of our VCSELs and SPADs improve by ~1000% while there has been little change in the analog technology used in other spinning lidar sensors.

1 comment:

  1. Does anyone know the size of Ouster's VCSEL and SPAD array? also does anyone know the fill factor or technology node of their SPAD?


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