150 nm tuning in a grating-coupled external cavity quantum dot laser

Summary form only given. A grating-coupled external cavity quantum dot laser with a 150 nm tunable range is presented. The lasing emission for various wavelengths is shown. The lasing linewidth is about 3 nm. Significantly, no failure of lasing occurs across the energy gap between the ground and the first excited states. This large tunable range is the product of the rapid carrier filling of the higher energy states under a low pumping current and homogeneous broadening in the quantum dot ensemble. The tunable range, slope efficiency and maximum power can be increased by decreasing the reflectivity at the AR facet and using a Littman-Metcalf external cavity configuration, which also decreases the linewidth. While extending the tuning range to longer wavelengths is limited due to the QD size and corresponding ground state energy, increasing to shorter wavelengths is feasible by taking advantage of the homogeneous broadening of the first and higher excited energy states.