Modulation bandwidth of a double tunnelling-injection quantum dot laser

Abstract

The modulation response of a double tunnelling-injection (DTI) quantum dot (QD) laser is studied. Closed-form expressions are obtained for the dynamic characteristics of the laser and the upper limit for the modulation bandwidth is estimated. The optimum cavity length, surface density of QDs, and dc injection current density, maximizing the modulation bandwidth, are shown to exist. The higher the dc injection current density, the smaller should be the optimum values of the cavity length and the surface density of QDs. While the maximum bandwidth is shown to be the same in DTI and conventional QD lasers and unaffected by the differential gain, the optimum dc current density, being inversely proportional to the differential gain, is lower in a DTI laser.

Optimizing the Quantum Dot Lasers for High-Speed Operation: Novel Versus Conventional Designs

“…The dynamic characteristics are also improved in DTI and ABL lasers as compared to conventional lasers [18][19][20][21]. Modulation bandwidth is an important parameter describing the speed with which the optical output of diode lasers is varied with altering the input injection current [18].…”