Forward electrical bias across the P-N junction causes the respective holes and electrons from opposite sides of the junction to combine giving off a photon in the process of each combination. The junction area's surfaces (cavity) are to a mirror like finish. Introduction: If you are about to begin working with laser diodes, you are most likely aware that their are some very. Laser diodes (LD) are semiconductor devices that convert electrical energy into high-power optical energy. These devices are currently used in the fields of telecommunications and medicine and in industrial cutting and welding applications. The example when 30mA is injected to LD on graph1 is as follows. If Tc is 60 degrees, Po might be about 1mW. They are widely used in various applications, including fiber-optic communication, barcode scanners, laser pointers, and optical storage devices.