High brightness GaSb-based optically pumped semiconductor disk lasers at 2.3 μm

Abstract

We report on recent advances in the performance of GaSb-based vertical-external-cavity surface-emitting lasers (VECSELs) emitting at wavelengths around 2.3 μm. Barrier-pumped VECSELs have been fabricated and analysed, which incorporates a diamond intra-cavity heat spreader as an efficient means for heat extraction from the active region. A maximum output power of 1.5 W has been achieved at a heat sink temperature of -20°C and still more than 1 W at 10°C. Two VECSEL structures with different spectral offsets uλ between the microcavity resonance and the maximum of the gain spectrum have been examined in particular. The results clearly show that the proper choice of this offset uλ is critical for an optimization of the high-power performance of the VECSEL, e.g. maximizing the output power before thermal rollover.