Narrow Linewidth of 633-nm DBR Ridge-Waveguide Lasers

Compact laser sources with long coherence lengths in the visible spectral region are sought for many applications. This letter presents distributed-Bragg-reflector (DBR) ridge-waveguide (RW) lasers with an emission wavelength at 633 nm and an optical output power >20 mW. The DBR-RW lasers exhibit a technical linewidth at full width at half maximum of ~1 MHz. The emission line can be tuned via current and temperature >200 GHz. At 14 mW, the lasers show a preliminary lifetime 4000 h.