Laser diodes have grown to a key component in modern photonics technology. This
article provides a general introduction in the physics and technology of laser diodes.
First the physical concepts behind laser diodes are explained. In the following an
example of an AlGaAs laser is given and analyzed in details. The last part introduces
technological approaches to build competitive laser diodes. The focus is thereby on
single mode laser diodes. We consider ways to introduce a waveguide in the laser diode
and concepts to make the laser diode wavelength selective. Briefly we take a look at laser
diode arrays for use in high power applications and finally we introduce the VCSEL’s
(Vertical Cavity Surface Emitting Lasers).