Experimental analysis of characteristic temperature in quantum-well semiconductor lasers

We experimentally analyzed the characteristic temperature T₀ in 1.3-μm GaInAsP-InP strained layer multiple-quantum-well (SL-MQW) semiconductor lasers by measuring temperature dependence of gain characteristics. We developed a new approach to evaluate the characteristic temperature, where the temperature dependence of the carrier lifetime estimated from the temperature dependence of the spontaneous emission intensity was taken into account. Our result showed that the temperature dependence of the threshold current is mainly determined by the temperature dependence of the spontaneous emission efficiency which reflects nonradiative recombination, carrier overflow effect, and carrier leakage effect. As a secondary effect, the current density dependence of the internal loss also affects the degradation of the characteristic temperature. The temperature dependence of the differential gain dG/dN and the transparency carrier density N_tr in the wells are not the dominant mechanism of the low characteristic temperature in GaInAsP-InP lasers around room temperature