Chirped multiple InAs quantum dot structure for wide spectrum device applications

A chirped multiple quantum dot (QD) structure is introduced as a means to controllably broaden the gain spectral width of InAs QDs. The In compn. and thickness of InGaAs strain-reducing layers (SRLs) can be used as tuning parameters to adjust the emission wavelength of each layer in the chirped stack. The spectral linewidth depends on the span of the In compn. and thickness of the InGaAs SRL. By varying the In compn. of each InGaAs SRL, a ground-state luminescence spectral width of 78 nm was achieved. The spectral width can be further increased by Be modulation-doping. The chirped multi-layer QD structure was used as the active region of a laser diode, exhibiting a lasing spectrum as wide as 30 nm. [on SciFinder (R)]