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Broadband Emission in Quantum-Dash Semiconductor Laser

In conclusion, the unprecedented broadband laser emission at room temperature up to 76 nm wavelength coverage has been demonstrated using the naturally occurring size dispersion in self-assembled Qdash structure. The unique DOS of quasi-zero dimensional behavior from Qdash with wide spread in dash length, that gives different quantization effect in the longitudinal direction and band-filling effect, are shown as an important role in broadened lasing spectrum as injection level increases. After an intermediate degree of postgrowth interdiffusion technique, laser emission from multiple groups of Qdash ensembles in addition to multiple orders of subband energy levels within a single Qdash ensemble has been experimentally demonstrated. The suppression of laser emission in short wavelength and the progressive red-shift of peak emission with injection from devices with short cavity length indicate the occurrence of photon reabsorption or energy exchange among different sizes of localized Qdash ensembles. These results lead to the fabrication of the wavelength tuned quasi-supercontinuum interband laser diodes via the process of IFVD to promote group-III intermixing in InAs/InAlGaAs quantum-dash structure. Our results show that monolithically integration of different gain sections with different bandgaps for ultra-broadband laser is feasible via the intermixing technique.

In conclusion, the unprecedented broadband laser emission at room temperature up to 76 nm wavelength coverage has been demonstrated using the naturally occurring size dispersion in self-assembled Qdash structure.