VCSELs

VCSELs

Multi-Junction VCSEL Array

Multi-Junction VCSEL Array

Lumentum multi-junction VCSEL arrays can reach extremely high peak power, in the hundreds of watts, when driven with short, nanosecond pulses at low duty-factors (<1%), making them ideal for short, medium, and long-range LiDAR systems.

The multi-junctions in these VCSEL chips reduce the drive current required for emitting multiple photons for each electron. Optical power above 4 W per ampere is common. The emitters are compactly arranged to permit not just high power, but also high power density. Lumentum has demonstrated over 1 kW per square mm of die area at 125°C at 0.1% duty cycle. 
 
For short distances, the VCSEL chip may be paired with a diffuser to illuminate a wide field of view. In this case, the higher power density reduces the chip area required.  For longer distances, higher power in a smaller area eases the LiDAR optical design so there can be more power collimated into lower divergence beams which can then scan the scene.  
 
VCSELs are more advantageous than multi-junction edge emitting lasers for LiDAR because of their narrower wavelength range over temperature and because they can be formed into addressable arrays of stripes or even a matrix-addressable format. Addressability permits replacement of mechanical LiDAR scanning with more robust, all-electronic LiDAR scanning. 
  
Lumentum leverages its proven high-volume VCSEL manufacturing platform for mobile products to produce VCSEL arrays for the automotive market. Thus, high peak power can be offered at high volume and high quality.

Multi-Junction VCSEL Array
Schematic of one emitter in a multi-junction VCSEL array