Structural Arrangement The intrinsic layer is sandwiched between the P-type and N-type layers. Much of the specifics are left to the user as any system can. The laser diode pinout is the guide for us to how to connect the diodes. You can see it the following drawing. This component is widely used in various applications, including but not limited to optical communications, barcode scanners, laser. When testing, one is at risk of applying wrong polarity to a laser: violating its reverse-voltage rating of 2V may cause destruction. To avoid this disaster, you might start with a voltage source set to slightly under 2V. That way, applying wrong polarity to the laser diode (LD) shouldn't cause. Laser diodes (LD) are semiconductor devices that convert electrical energy into high-power optical energy.