The difference between the fiber laser and the semiconductor laser is that the dielectric material that they emit the laser is different. The gain medium used by the fiber laser is fiber, the gain medium of the semiconductor laser is the semiconductor material, generally the gallium arsenide and the indium gallium, etc. (in the same way, the gain medium of the solid state laser is generally crystal or glass, ceramics. The mechanism of the luminescence of a semiconductor laser is the transition between the conduction band and the valence band. Because it is a semiconductor, it is a direct electrooptic conversion using electrical excitation. And the optical fiber can not directly realize the electro-optical conversion, and the gain medium is pumped with light (general excitation). Photodiode pumped), it realizes light and light conversion.<br/>The fiber laser has good heat dissipation and air cooling. Semiconductor lasers are very affected by temperature. When power is large, water cooling is needed.<br/>A semiconductor laser is a laser using a solid laser material as a working substance. It is usually made up of a laser working substance, Ji Liyuan, a lumen, a resonator mirror and a power source. The solid working substance used in this type of laser is made of a metal ion that can produce stimulated emission in a crystal.