The fundamental test of a laser diode is a Light-Current-Voltage (LIV) curve, which simultaneously measures the electrical and optical output power characteristics of the device. This test is primarily used to sort laser diodes or weed out bad devices before they can be built into an. Author: the photonics expert Dr. 61835/8ab. Over 99% of all lasers manufactured in the world today are semiconductor laser diodes. NI recommends that you calibrate the responsivity and dark current of the external photodetector (ePD) before testing an. Laser diodes are essential components in various applications, and ensuring their reliability and performance is crucial.