Narrow linewidth 2 µm GaSb-based semiconductor disk laser

In this contribution the authors report on the realization of tunable, narrow-linewidth GaSb-based OPSDLs emitting in the 2.0 - 2.35 μm wavelength range. The V-shaped laser cavity, schematically shown in the paper, is placed inside a stable, sealed and compact module housing in order to provide the necessary mechanical stability. The module is temperature stabilized to 20°C using a standard TEC element. For wavelength control and in order to enable single frequency emission, a quartz plate is inserted acting as a birefringent filter and the laser cavity is optimized for TEM₀₀ mode emission. Using a high-finesse Fabry-Perot interferometer (FPI), stable single frequency operation was verified with an output power above 200 mW. Coarse wavelength tuning of up to 118 nm was achieved by rotating the quartz plate. By mounting the output coupling mirror onto a piezoelectric transducer (PZT), modehop-free fine-tuning of the laser wavelength of over 5 GHz was achieved, limited by the maximum travel of the PZT driven output coupling mirror.