The positive and negative terminals of the laser diode represent the anode and cathode connections, respectively. Laser diodes have several important characteristics that make them unique. Precautions required to avoid excessive currents, static electricity and heat generation are detailed and the drive. The purpose of this laser diode tutorial is to provide the information necessary to create a long lifetime, stable laser diode system. Much of the specifics are left to the user as any system can. A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction.