2.5 W GaSb-based VECSEL at 2062.4 nm with an absolute wavelength stability below 1 MHz

We present a GaSb-based vertical-external-cavity surface-emitting laser (VECSEL) tailored as a low-noise pump source for quantum frequency conversion. The 2062.4 nm emitting VECSEL emits a single-frequency output power of 2.5 W in a linear cavity with an intracavity birefringent filter. With no additional means of wavelength stabilization, the emission wavelength drift over 15 hours was less than 7 pm after the initial thermalization period. After locking the VECSEL to a frequency comb, the beating frequency between the laser and the comb light was characterized. The measurement confirmed a linewidth of less than 350 kHz (FWHM), and the absolute wavelength deviation over 22 hours had a standard deviation of 103.6 kHz. Relative intensity noise (RIN) measurements showed an integrated RIN of 0.15% root mean squared (RMS).