Mid-infrared laser diodes investigation via low-frequency noise spectroscopy and electrical derivative characteristics

Electrical noise and electrical derivative (ED) characteristics of different heterostructure GaSb-based type-I mid-infrared laser diodes (LDs) are investigated in order to find a relation between these characteristics. The measurement results demonstrate that the manner of electrical noise voltage spectral density dependence on forward current in subthreshold region could be predicted from ED characteristics. Low-frequency noise spectroscopy, a sensitive diagnostic tool, during the LDs aging experiment reveals major changes in cross-correlation between electrical and optical fluctuations attributed to slight LDs degradation and also a non-optimum LD facet coating process as an additional noise source.