Semiconductor laser introduction
A semiconductor laser, also called a laser diode, is a laser that uses a semiconductor material as a working substance. Due to differences in material structure, the specific processes for producing lasers of different types are special. Common working materials include gallium arsenide (GaAs), cadmium sulfide (CdS), indium phosphide (InP), and zinc sulfide (ZnS). The excitation methods are three forms: electric injection, electron beam excitation and optical pumping. Semiconductor laser devices can be classified into homojunction, single heterojunction, and double heterojunction. Homogeneous junction lasers and single heterojunction lasers are mostly pulsed devices at room temperature, while double heterojunction lasers can operate continuously at room temperature.
Semiconductor diode lasers are the most practical and important class of lasers. Its small size, long life, and simple injection current to pump its operating voltage and current are compatible with the integrated circuit, so it can be integrated with it. It is also possible to directly perform current modulation with a frequency up to GHz to obtain a laser output of high speed modulation. Due to these advantages, semiconductor diode lasers have been widely used in laser communication, optical storage, optical gyro, laser printing, ranging, and radar.