1550 nm High Power Broad Area Laser with InGaAlAs-MQWs as active Material and Al-free Facets

NIR-semiconductor lasers with an emission wavelength beyond 1300 nm are of crucial interest for a wide range of industrial and medical applications such as plastics welding and surgery [1]. For such lasers the InPmaterial system is the well proven candidate of choice. We already demonstrated a 1550 nm broad area laser with a 20°C optical output power as high as 4.9 W in CW mode by using strained InGaAsP quantum wells (QW) as active material [2]. InGaAlAs QWs could potentially offer an enhanced performance at elevated operation temperatures because of a stronger confinement of the electrons due to the potentially larger conduction band offset [3]. Unfortunately, the facets of Al-containing QWs tend to degrade quickly when being exposed to air. In particular but not exclusively for high power devices this becomes a severe problem causing catastrophic optical damage (COD). Cleaving in UHV and sophisticated cleaning technics prior to mirror coating [4] reduce the degradation, but come with significant expense.