Laser diodes are current driven and current sensitive semiconductors. Any instability in the drive current (noise, drift, induced transients), will affect the laser diode's performance. 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. : 3 Driven by voltage, the doped. This set of control elements are combined to produce what is commonly called a laser diode driver. More ». A proper laser diode driver circuit is critical for reliable operation and long device lifetime.