Electronic tuning of integrated blue-violet GaN tunable coupled-cavity laser

We demonstrate an integrated tunable coupled-cavity InGaN/GaN laser with the emission wavelength centered on 409 nm. The electronic tuning range was 1.6 nm and threshold currents were 650 mA per cavity for 8.7-μm-wide laser ridges. Multimode laser emission with an average full width at half maximum of 0.3 nm was observed. We estimate the refractive index change due to free-carrier injection and optical gain to explain the experimental tuning range.