Dynamics and temperature-dependence of 1.3-μm GaInNAs double quantum-well lasers
Journal article, 2006
We have measured the small-signal modulation response of 1.3-μm ridge waveguide GaInNAs double quantum-well lasers over a wide range of temperatures (25 μC-110 °C) and analyzed the temperature dependence of the modulation bandwidth and the various bandwidth limiting effects. The lasers have low threshold currents and high differential efficiencies with small temperature dependencies. A short-cavity (350 μm) laser has a modulation bandwidth as high as 17 GHz at room temperature, reducing to 4 GHz at 110 °C, while a laser with a longer cavity (580 μm) maintains a bandwidth of 8.6 GHz at 110 μC. We find that at all ambient temperatures the maximum bandwidth is limited by thermal effects as the temperature increases with current due to self-heating. The reduction and subsequent saturation of the resonance frequency with increasing current is due to a reduction of the differential gain and an increase of the threshold current with increasing temperature. We find large values for the differential gain and the gain compression factor. The differential gain decreases linearly with temperature while there is only a weak temperature dependence of the gain compression. At the highest temperature we also find evidence for transport effects that increase the damping rate and reduce the intrinsic bandwidth.