HIGH POWER LASER DIODE LIFETIME AND DEGRADATION MECHANISMS: A STUDY BY RAMAN MICROPROBE SPECTROSCOPY

Abstract

  For advanced semiconductor lasers, the maximum output power as well as the lifetime is limited by localized facet heating leading to mirror degradation and the occurrence of catastrophic optical damage (COD). The measurement of the laser facet temperature rise behavior, however, is a difficult task because of the small dimension of the lasing region. Utilizing microprobe Raman spectroscopy, we were able to systematically study the laser facet heating behavior with good temperature sensitivity and sub-micron spatial resolution. From these temperature rise data, wc have gained a better understanding of the physics and chemistry of laser diode facet degradation and the mechanisms leading to COD. The relationship of facet temperature to maximum laser output power and lifetime is discussed.