Advantages of Different Wavelength Lasers
Self-driving vehicles, which were the subject of science fiction even 20 years ago, are now poised to become a reality. Companies like Google, Uber, Tesla, and Toyota are all developing different levels of self-driving cars. Have you seen these autonomous vehicles on the streets yet? These cars are equipped with a LiDAR system mounted on top. In the absence of a driver, a LiDAR system becomes the eyes of the vehicle, continuously monitoring the environment to safely guide it to its destination. Most self-driving cars today use a combination of LiDAR, radar, and cameras to create a 3D map of their surroundings.
LiDAR stands for Light Detection and Ranging. The technology has been around for many years and was primarily used in archaeology and geological mapping applications. LiDAR uses laser pulses that bounce off objects and return to the sensor to measure distances and create a detailed 3D map. Since LiDAR systems produce their own light sources, they are ideal for both day and night operation.
Originally, autonomous vehicles used 905 nm laser diodes in their LiDAR systems because they were inexpensive. Silicon avalanche photodiodes, which work with these lasers, are also relatively affordable. Additionally, 905 nm lasers provide reasonably good atmospheric transmission. However, there are a few limitations to this system. Because this wavelength can damage the human eye, pulse power must be limited, which means these systems do not perform well in bad weather. The low pulse power also limits the detection range to approximately 100 meters.
Another approach is to use a higher wavelength 1550 nm laser. This wavelength is widely used in telecommunications and is not harmful to the eye. The higher pulse power allows for a longer detection range of 200 meters or more and more efficient penetration in poor weather conditions. LiDAR systems using 1550 nm wavelengths are generally more expensive because they require costly Indium Gallium Arsenide (InGaAs) photodetectors and cannot use cheaper silicon photodiodes.
Different wavelengths have different advantages and disadvantages in LiDAR applications. Selecting the right wavelength depends on various factors such as cost, range, and intended application. Optical component costs will continue to decrease as production volumes increase, and the day when your groceries are delivered by a self-driving car may not be far away.
Vitex has the right lasers and photodiodes to support LiDAR applications. Contact us at 201-296-0145 or info@vitextech.com if you have any questions.
