Damping limited modulation bandwidths up to 40 GHz in undoped short-cavity InGaAs-GaAs multiple quantum well lasers

Abstract

We demonstrate record direct modulation bandwidths from MBE-grown In0.5Ga0.65As-GaAs multiple-quantum-well lasers with undoped active regions and with the upper and lower cladding layers grown at different growth temperatures, Short-cavity ridge waveguide lasers achieve CW direct modulation bandwidths up to 40 GHz for 6 x 130 mu m(2) devices at a bias current of 155 mA, which is the damping limit for this structure, We further demonstrate large-signal digital modulation up to 20 Gb/s (limited by the measurement setup) and linewidth enhancement factors of 1.4 at the lasing wavelength at threshold of similar to 1.1 mu m for these devices.