Broadband tuning (ΔE∼100 meV) of Alx Ga1−xAs quantum well heterostructure lasers with an external grating

Abstract

Al_x Ga_1−xAs‐GaAs quantum well heterostructure laser diodes are shown to be tunable over a 100‐meV range when operated continuously (cw) at room temperature in an external cavity with a grating to control feedback. The gain profile of the n=1 and n′=1′ (electron‐to‐heavy hole and electron‐to‐light hole, e→hh and e→lh) transitions and the n=2 electron‐to‐heavy hole transitions are clearly outlined by the intensity profile of the selected laser lines. The partial homogeneous broadening of the gain profile agrees with rapid carrier relaxation in the well. The diodes contain a single 60–90‐Å GaAs well and are grown by metalorganic chemical vapor deposition.