Increase of the threshold current of InGaAsP heterolasers during aging at elevated temperatures

An investigation was made of the service life of InGaAsP heterolasers (σ = 1.3 μm) over periods of 3 X 10⁴ h at Т = 65 °C. Expressions describing an increase in the threshold current during tests were obtained. It was found that the relative change in the threshold current could be used in quality control of heterolasers and in selection of samples with a long expected service life.