Widely tunable GaSb-based external cavity diode laser emitting around 2.3 µm

We report on a widely tunable external cavity GaSb-based diode laser (ECL) in Littrow-configuration. The low (44° full-width at half-maximum) fast axis beam divergence of the quantum-well diode laser employed allowed an efficient coupling to the external cavity, which resulted in a wide tuning range of 177 nm around the central emission wavelength of 2.30 µm. The maximum output power of the fiber coupled ECL system varied only moderately between 16.5 mW at 2.23 µm and 9 mW at the long-wavelength limit at 2.39 µm.