Tunable dual-wavelength coupled-cavity semiconductor lasers

We experimentally demonstrate twin-microsquare and microsquare-Fabry-Pérot (FP) coupled-cavity semiconductor lasers. By adjusting the injection currents, dual-wavelength lasing with tunable frequency differences ranging from ∼12 to ∼235 GHz and a wavelength tuning range of ∼10 nm is respectively achieved for the twin-microsquare and microsquare-FP lasers.