Temperature dependence of electrical and optical modulation responses of quantum-well lasers

Abstract

Abstract-We present theory and experiment for high-speed optical injection in the absorption region of a quantum-well laser and compare the results with those of the electrical injection in cluding carrier transport effect. We show that the main difference between the two responses is the low-frequency roll-off. By using both injection methods, we obtain more accurate and consistent measurements of many important dynamic laser parameters, which include the differential gain, carrier lifetime, � factor, and gain compression factor. Temperature-dependent data of the test laser are presented which show that the most dominant effect is the linear degradation of differential gain and injection efficiency with increasing temperature. While the �-factor is insensitive to temperature variation for multiple-quantum-well lasers, we find that the carrier capture time and nonlinear gain suppression coefficient decreases as temperature increases.

Intrinsic Dynamics of Quantum-Dash Lasers

“…The measured modulation response fits very well [see Fig. 3(a)] the classic frequency dependence of quantum-well lasers [23] …”

Theory and experiment of high-speed cross-gain modulation in semiconductor lasers

“…The relaxation frequency peaks are at 2.1, 4.8, and 6.2 GHz at biases of 15, 25, and 40 mA, respectively. Optical modulation directly mod ulates the carrier density in the same manner as current modu lation (electrical modulation), but removes carrier transport ef fects and the circuit parasitics, which contribute to an additional low-frequency roll-off in the modulation response [24]. At low current bias, even the relaxation frequencies of electrical and optical modulation are close, and the optical gain modulation still shows a higher relaxation peak.…”

“…The slope of the linear fit of the damping factor versus relaxation frequency squared is the factor (23) (24) Fig. 5(a) shows that the factor increases with increasing pump power, as predicted by (24), but the change is very small. In Fig.…”

“…The normalized modulation response is obtained according to the low-frequency value , which is referred to as the signal level. The optical XGM experiments are performed in a manner similar to the optical pump experiments of pumping in the absorption region in [24]. However, there are a few important differences in procedure which must be followed.…”

“…Several groups have measured the optical-absorption modu lation response of a semiconductor laser for optical pumping within the QW region, where the pump photons create elec tron-hole pairs as they are absorbed [19], [23], [24]. The newly created carriers relax into the lower states of the QW, modu lating the QW carrier density and the laser output.…”