Reliability study on high-power 638nm broad stripe laser diode

High-power laser diodes (LDs) are strongly demanded as a light source of display applications. In this work, the reliability of a high-power 638 nm broad stripe (BS) LD was studied from the viewpoint of not only gradual degradation but also catastrophic optical degradation (COD) at a front facet. Long term acceleration aging tests for the 638 nm BS-LD with the window-mirror structure by using Zn diffusion were performed. It was confirmed that COD only occurs at a high output power and this mode was dominant compared with gradual degradation. The result also revealed that the mean time to failure due to COD was proportional to optical density to the power of ?3:2. It is clarified that maintaining a low optical output power density is essential to develop high-power and highly reliable red BS-LDs.