Features of VCSEL
Because the VCSEL and the edge-emitting laser have distinct structures, which determines the variations in their characteristics and performance, the basic parameters of the two lasers are shown in the table below.
Comparison of structure and performance between edge-emitting laser and VCSEL
The table shows that the VCSEL active region is small and has a short cavity, making single longitudinal mode, low threshold (sub-milliamp) current operating easier. The active zone, on the other hand, must be larger in order to get a sufficiently high gain. The reflectivity of the hollow mirror must be at least 99 percent. VCSEL is expected to be used in a wide range of high-speed data transfer and optical communications applications due to its high relaxation oscillation frequency. A VCSEL's light emission direction is perpendicular to the surface of the substrate, allowing for good lateral light field restriction. The full wafer test yields a circular beam, and the fabrication of a two-dimensional array is simple. The epitaxial wafer can reduce production costs before the full process is completed.
The Advantages of VCSEL
l. The outgoing beam is circular with a modest divergence angle, making it simple to couple with optical fibers and other optical components while also being very efficient.
2. It has the ability to perform high-speed modulation and can be used in long-distance, high-speed optical fiber communication systems.
3. Because the active area is tiny, single longitudinal mode and low threshold operation are simple to produce.
4. The electro-optical conversion efficiency could be larger than 50%, implying a longer gadget life. 5. It is simple to implement a two-dimensional array, apply it to a parallel optical logic processing system, achieve high-speed, large-capacity data processing, and use it in high-power devices.
6. The chip can be tested and the product screened before it is packaged, lowering the product's cost significantly.
7. It can be employed in laminated optical integrated circuits with micromechanical technology.