A laser diode driver is an electronic instrument that precisely controls the electrical current delivered to a laser diode, enabling stable, repeatable, and safe optical output. It regulates both current amplitude and voltage to protect the diode from overcurrent damage — even brief current spikes can permanently destroy a laser diode. Pulsed laser diode drivers, like the Berkeley Nucleonics PCX Series, add precise timing control with nanosecond-level pulse widths and adjustable repetition rates, which is essential for applications in LIDAR, time-resolved spectroscopy, medical instrumentation, rangefinding, and materials processing.