VCSEL, Vertical Cavity Surface Emitting Laser (VCSEL), short for Surface Emitting Laser. Based on gallium arsenide semiconductor materials, different from the LED (light emitting Diode) and LD (Laser Diode and Laser Diode), and other light source, has small, round output light spot, single longitudinal mode output, small threshold current, low cost, easy integration of the advantages of large area array, widely used and optical communications, optical interconnection, optical storage, and other fields.

The key process of VCSEL is, in general, epitaxy: using MOCVD (organic gas-phase epitaxy deposition) and MBE (molecular beam epitaxy) technologies; Lithography: determination of chip graphics and size, icp-rie (inductively coupled reactive ion etching) technology etching the starting light platform (Mesa); Oxidation: let the resonant cavity define the best VCSEL optoelectronic characteristics; Passivation: the insulation process allows exposed semiconductor materials to be free from air and water vapor influence reliability; Grinding and cutting: turn into one chip, then test and send to the sealing factory. The structure is similar to red and yellow LED chip, which is vertical structure of upper and lower electrodes.

Indeed, as you said, after the application of VCSEL to 3D sensing by apple iPhone X, the industry has increased the layout of VCSEL. It is mainly realized that the VCSEL is the best choice for future production of many facilities and devices requiring sensors. Since multiple lasers can be lined up in parallel in the direction perpendicular to the substrate, VCSEL is very suitable for parallel optical transmission and parallel optical interconnection, etc. VCSEL can be used to transmit data at high speed in optical fiber network, which can transmit more data at higher speed than traditional cable system. Speeds of 40G/s are currently the highest in the United States in this field. Because of its small size, the VCSEL device also has high energy efficiency, saving 100 times more energy than conventional power lines. But at the same time its data transmission accuracy is very high.

The VCSEL has a promising future in optical communications, and now the iPhone X is applying the technology to 3D sensing. In terms of the 3D sensing market alone, more than 1 billion smart phones are consumed worldwide every year. If every phone is embedded with 2-3 VCSEL laser devices, the market size will be 2 or 3 billion.