Gain-switched pulses from InGaAs ridge-quantum-well lasers limited by intrinsic dynamical gain suppression

Gain-switched pulses of InGaAs double-quantum-well lasers fabricated from identical epitaxial laser wafers were measured under both current injection and optical pumping conditions. The shortest output pulse widths were nearly identical (about 40 ps) both for current injection and optical pumping; this result attributed the dominant pulse-width limitation factor to the intrinsic gain properties of the lasers. We quantitatively compared the experimental results with theoretical calculations based on rate equations incorporating gain nonlinearities. Close consistency between the experimental data and the calculations was obtained only when we assumed a dynamically suppressed gain value deviated from the steady-state gain value supported by standard microscopic theories.