The difference between surface and edge emitting LED.

Surface emitting LEDs are also known as vertical cavity surface emitting lasers (VCSELs). They emit light perpendicular to the surface of the semiconductor wafer. Edge emitting LEDs, on the other hand, emit light from the edges of the wafer, parallel to its surface. The main advantages of surface emitting LEDs are their higher efficiency, lower power consumption, and ability to be fabricated in large numbers on a single wafer. Edge emitting LEDs, however, are generally more powerful and can be used for applications that require higher output power, such as fiber optic communications.