Abstract
A new method is proposed for analysing the static characteristics of laser diodes, specifically the current leakage which is characteristic of buried heterostructure lasers and deteriorates their high performance. The new method is based on the fact that the junction voltage saturates over threshold. From a combination of the derivatives of experimental current-voltage and current-light characteristics the internal resistances of laser diodes are obtained in a simple graphical way and the electrical characteristics of leakage are obtained without specific assumptions on the functional relation between current and voltage. The new method is applied to the 1.3 mu m wavelength InGaAsP VSB-type lasers in which current leakage is anticipated. It gives adequate values for internal resistances and the amount of leakage current, and suggests the position of leakage.