Long-Term Aging and Quick Stress Testing of 980-nm Single-Spatial Mode Lasers

Single-spatial mode lasers emitting at 980 nm are studied during continuous-wave long-term operation and ultra-high power short-term operation (stress-test) up to 13.5 W. We find that both tests eventually activate the same degradation mechanism, namely internal catastrophic optical damage. In the case of ultra-high power operation, we show that the mechanism that initializes this effect is a lateral widening of the optical mode, resulting in increased absorption outside the waveguide. Defects formed during long-term aging may eventually lead to the same effect. Stress testing allows for activation of several degradation mechanisms in a device one after the other and for distinguishing between mechanisms induced by aging and independent ones. Stress tests could pave the way toward more time-efficient testing, e.g., for comparison of different technology variants in development.