ams, a leading worldwide supplier of high-performance sensor solutions, announced that it has joined forces with Ibeo Automotive Systems, a supplier of automotive LiDAR sensor technology, and ZF Friedrichshafen, a provider of automotive systems, to advance solid-state LiDAR technology for use in autonomous driving and other applications.
ams will be providing VCSEL arrays as the light source through which these LiDAR systems function.
How LiDAR Works
LiDAR, which stands for Light Detection and Ranging, is a sensing technology akin to RADAR. But, while radar detects objects by the reflection of radio waves off their surface, LiDAR illuminates them with a laser beam and detects the bounce-back of the laser signal.
LiDAR. Image from ams
Laser wavelengths are much shorter than radar wavelengths. Because of this, the exact position of the detected object, such as a pedestrian or another moving vehicle, can be measured far more accurately.
It is expected that LiDAR systems will be used in conjunction with existing solutions such as RADAR and cameras. The ultimate goal is to achieve the “Holy Grail” of the self-driving car industry—SAE level 5, or fully autonomous driving.
What Is Solid-State LiDAR? (What's the Big Deal, Anyway?)
Solid-state LiDAR is a form of LiDAR that does not require moving parts. Built entirely on a silicon chip, a solid-state LiDAR system is smaller and more resilient to vibrations—and oftentimes less expensive than an electromechanically-intensive traditional LiDAR system. Where a typical automotive LiDAR system was mounted to a vehicle and physically moved to change its direction, solid-state LiDAR is capable of adjusting its directional focus by changing the patterns of its optical emissions. This is obviously attractive to the designer of an autonomous vehicle as it eliminates the need for a swiveling LiDAR sensor mounted to a vehicle (or a multitude of LiDAR sensors locked in place to cover blind spots).
A traditional LiDAR system mounted to the top of a Waymo vehicle. Image from Waymo
Additionally, the enhanced immunity to vibrations is obviously interesting for rugged environments such as those found in automotive applications.
As Dr. Ulrich Lages, CEO of Ibeo Automotive Systems, puts it: “LiDAR is already a key technology in the automotive sector, and to date our leading products are used with automotive companies in Europe and worldwide. The combination of our solution know-how with ams’ VCSEL technology will create a tipping point for solid-state LiDAR in the automotive sector."
So what is does this ams technology offer?
What Is VCSEL Technology?
VCSEL stands for vertical cavity surface emitting laser. A key distinction VCSEL is that laser light is emitted vertically from the wafer, as opposed to horizontally as in the case of edge emitting lasers.
VCSEL lasers emit light vertically from the wafer, as opposed to horizontally as in the case of edge emitting lasers. Image from SPIE, the international society for optics and photonics
This is a key advantage in manufacturing, because VCSELs can be tested while still on-wafer. This slashes production costs because malfunctioning devices can be discarded immediately. Standard edge emitting lasers can only be tested much later in the production process, after the costly process of cleaving into individual units and building them into larger structures.
Edge-emitting has a high divergence angle, while VCSEL has a circular light beam, which is much easier to couple into optical fiber.
VCSELs also require lower current threshold to turn on, so they use less power. In addition, they have lower sensitivity to temperature, a key metric for automotive electronics.
“Being the first to market with solid-state LiDAR means ams brings a unique capability to Ibeo and ZF,” said Alexander Everke, CEO, ams. “Together with Ibeo’s leading solutions and integration capability, coupled with its deep experience in LiDAR we will provide an unmatched solution for automotive manufacturers in their quest to create the mission-critical reliability required for autonomous driving.”
Time of flight (ToF) measures the time it takes for the laser pulse to leave the VCSEL, impinge on the target and to return. Plugging in the speed of light allows the distance to be calculated.
While this partnership represents a new level of commitment to automotive applications of VCSEL, the concept itself is not new.
Here are a few examples:
- Finisar's HVS7000 product line devices are designed to integrate optics such as a diffuser. This series is AECQ- and Jedec-qualified and operates over a temperature range of -40°C to +125°C. Several members of this product line are suitable for time-of-flight (ToF) applications.
- Vertilite offers a wide range of VCSEL products, including the CAS8502W. Typical applications include ToF, automotive sensing, and infrared illumination.
Do you have experience designing with LiDAR, solid-state or otherwise? Tell us about it in the comments below.