3D Sensing: VCSEL Laser Illumination

1. VCSEL Overview

2. VCSEL vs EEL and LED

3. VCSEL Features

VCSELs can have a high beam quality only for fairly small mode areas (diameters of a few microns) and are thus limited in terms of output power. For larger mode areas, the excitation of higher-order transverse modes can not be avoided; this is a consequence of the extremely small resonator length of only a few microns, and the difficulty in homogeneously pumping a larger active region with a ring electrode. The short resonator, however, also makes it easy to achieve single-frequency operation, even combined with some wavelength tunability. Also, VCSELs can be modulated with high frequencies, making them useful e.g. for optical fiber communications (see below).

4. VCSEL Arrays

Much higher powers can be generated with VCSEL arrays. A 2-D VCSEL array containing many thousand emitters (with a spacing of some tens of microns) can emit tens or hundreds of watts continuous-wave, thus competing with diode bars. In principle, the output power can simply be scaled up (“power scaling”) by increasing the number of emitters, but the beam quality it is often strongly reduced. However, there are also approaches where the emission of all the VCSELs of an array is coordinated (made coherent), which results in a far better beam quality and accordingly increased radiance, despite some loss of power conversion efficiency.

5. How to Make VCSEL

6. Applications, 3D Sensing and Considerations

VCSELs have many applications, the most important of which are briefly discussed in the following: Optical Communications, Computer Mice, Gas Sensing, Optical Clocks, Laser Pumping, and 3D sensing.

7. Evolution of VCSEL Package

  1. https://www.rp-photonics.com/vertical_cavity_surface_emitting_lasers.html
  2. Abax http://www.abax-sensing.com/newsInfo-10-9.html
  3. https://www.thorlabs.com/tutorials.cfm?tabID=3F8928B5-A77C-46A2-877F-07C1D83AD018
  4. VCSELs: Fundamentals, Technology and Applications of Vertical-Cavity Surface-Emitting Lasers 2013
  5. https://www.newmetals.co.jp/pdf/234.pdf
  6. https://www.semiconchina.org/Semicon_China_Manager/upload/kindeditor/file/20190415/20190415103954_498.pdf

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For 4D Sensing, AR, AV/Robot, and AIoT

Marc. Y. , Tech Leader. Focus on new techs such as 4D Sensing, AR, AV/Robot, and AIoT. More at http://4da.tech/