Properties of planar stripe-geometry heterojunction lasers. II. Analysis of electrical characteristics

An investigation was made of differential current-voltage characteristics of cw planar stripe-geometry heterojunction lasers at room temperature. In these lasers, the current-power characteristics frequently have anomalies in the form of nonlinearities, nonmonotonic behavior discontinuities, and power hysteresis loops. It is shown that these characteristics are accompanied by certain features of the electrical characteristics, for example, of the function $IdU/dI$, where $U$ is the voltage across the diode and $I$ is the pump current. Thus, by observing the current-voltage characteristics, it is possible to identify anomalies in the laser action without optical measurements. If the photoelectric effect inside the diode does not mask the fundamental relationship between the optical and electrical characteristics, an anticorrelation is observed between the differential resistance and the differential efficiency of the laser. An analysis is made of an idealized model of the current-voltage characteristic of an injection laser and a modification of this model is used to interpret (at least qualitatively) the observed relationship between the current-voltage and current-power characteristics.