We report on the design and characterization of multi-mirror vertical-cavity surface-emitting lasers (VCSELs) that achieve linewidths less than 2 MHz. We have fabricated all-semiconductor multi-mirror VCSELs at 850 nm that operate in a single mode and are suitable for high-resolution spectroscopy. Cold-cavity linewidth measurements confirm increased quality factors relative to standard VCSEL resonators. Frequency noise power spectral density measurements exhibit 1/f noise and white-noise floors consistent with Lorentzian linewidths less than 2 MHz.
We report on mode selection and tuning properties of vertical-external-cavity surface-emitting lasers (VECSELs) containing coupled semiconductor and external cavities of total length less than 1 mm. Our goal is to create narrowlinewidth (<1MHz) single-frequency VECSELs that operate near 850 nm on a single longitudinal cavity resonance and tune versus temperature without mode hops. We have designed, fabricated, and measured VECSELs with external-cavity lengths ranging from 25 to 800 μm. We compare simulated and measured coupled-cavity mode frequencies and discuss criteria for single mode selection.