Quantum Dot-Rolled-up and Edge Emitting Lasers

Due to their unique optoelectronic properties, lasers incorporating quantum dots exhibit superior characteristics compared with those incorporating equivalent quantum wells and quantum dashes. The three-dimensional confinement of carriers in the quantum dots produces an atomic-like density of states which results in better temperature stability, chirp-free high speed operation, higher modulation bandwidth in the lasers and therefore makes them a favorable candidate for practical applications.
The threshold behavior of novel GaAs based InAs quantum dot rolled-up microtube lasers has been investigated. The threshold condition was derived considering the radiation, bending, and substrate losses associated with these device geometries and verified with experimental data. A microtube directional coupler sensor and a microtube phototransceiver circuit have also been demonstrated. The growth of self-organized InAs/In0.53Ga0.23Al0.24As quantum dots on InP substrates for 1.55 Â µm lasers has been achieved by limiting the anisotropic migration of In adatoms on the growth surface. Quantum dot lasers incorporating tunnel injection and modulation p-doping of the active region have been demonstrated. These lasers are characterized by high temperature stability with a characteristic temperature To ~227 K in the temperature range 5 to 45 oC and a maximum 3-dB modulation bandwidth of 14.4 GHz has also been achieved.