Recent Advances in Power Scaling of GaSb-Based Semiconductor Disk Lasers

GaSb-based semiconductor disk lasers (SDLs) cover the application-rich 2-3-μm wavelength range. The output power of these lasers is mainly limited by the active region heating and resulting thermal rollover, caused by the waste heat deposited in SDL chip. We present recent advances achieved in 1) reducing the heat load on the SDL chip by reducing the quantum deficit, and 2) removing the waste heat more efficiently by combining front- and backside heat sinking. The latter step was based on extensive thermal simulations of the heat distribution and heat flow within SDL chip and submount, which are also presented. Combining both approaches, we could demonstrate 20 W of continuous wave output power from a GaSb-based single-chip SDL operating at 2 μm and a heat sink temperature of 0 °C. A comparative analysis of the similarities and differences to GaAs-based SDLs emitting around 1 μm is given.