Introduction

Intent

Although light emission can occur as soon as current is applied to the semiconductor laser, it does nor emit coherent light until the current exceeds a critical value, known as the threshold current. The threshold current is one of the most important parameters for lasers.

This procedure provides standard measurement techniques for semiconductor lasers. This procedure covers the measurement of the threshold current of semiconductor lasers either as a laser chip placed on a surmount to facilitate handling or as an assembled laser package.

Hazards

This procedure involves potentially hazardous operations as discussed in this section. During the measurement, a laser will emit non-visible light. Personnel are strongly cautioned never to look directly into the laser at any time. Although the optical output power is generally not very high, virtually all the power is concentrated into a narrow frequency band, which implies that the energy can be focused into a very intense spot on the retina by the lens within the viewer's eyes.