Effects of nonuniform well width on compressively strained multiple quantum well lasers

Abstract

We theoretically investigate the effects of nonuniform well widths on compressively strained In0.2Ga0.8As/GaAs multiple quantum well lasers using multiband effective mass theory and density matrix formalism. We find that the well width fluctuations do not degrade the transparency current, differential gain, and linewidth broadening factor. Besides, lasers with intentionally designed chirped well width have much broader gain profiles compared to uniform well lasers. This feature is attractive for applications requiring large gain bandwidth such as tunable lasers, mode-locked lasers, and wavelength division multiplexed laser arrays.