Low-frequency noise measurements as an analysis and prediction tool for the reliability evaluation of 808 nm laser diodes.

We investigated the low-frequency optical and electrical noise characteristics and their cross-correlation factor of the 808 nm laser diodes (LDs) samples, whose performances were degraded and stabilized after operating a period of time or during ex-factory reliability lifetime tests. It was shown that the optical noise in unreliable samples exhibited white components in the frequency range from 1 kHz to 10 kHz, while a Lorentzian-type component was superimposed on 1/f electrical noise. Meanwhile, the optical and electrical noise correlation exhibited positive result. In contrast, both low-frequency optical and electrical noise presented pure 1/f-type fluctuations in stable samples. These presented results suggest that it is feasible to employ low-frequency noise measurements as a tool for predicting and diagnosing the reliability of LDs.