Determination of the Limiting Characteristics of a Laser-Diode Bar by Analyzing Emission in the Near Field.

The spatial distribution of the emission intensity in the near field of a laser-diode bar with a wavelength of 808 nm is obtained experimentally. During the experiments, laser diodes operate in the quasi-continuous lasing mode in the range of injection currents from the threshold value to the onset of degradation of individual laser diodes. On the basis of analysis of the distribution of the emission intensity in the near field in the direction parallel to epitaxial layers, a system of parameters is proposed that makes it possible to obtain a probabilistic estimate of the limiting value of the injection current of individual diodes. During optical inspection of the surface of the laser diodes, it is found that the failure of individual diodes in most cases occurs due to catastrophic optical degradation of the semitransparent mirror of a laser cavity formed on the cleaved surface of a semiconductor. The proposed system of parameters includes both previously known and new ones: the ratio of the maximum and average values of the intensity of laser diodes in the spatial distribution, the standard deviation of the intensity, and a parameter that takes into account the emission intensity of edge-emitting laser diodes. As a result of analysis of the spatial distribution of the emission intensity in the near field of a laser-diode bar in the working section of the light–current characteristic, it is possible to single out individual laser diodes characterized by the lowest limiting injection current and to predict the development of degradation processes. [ABSTRACT FROM AUTHOR]