Study on the dominant mechanisms for the temperature sensitivity of threshold current in 1.3-mu m InP-based strained-layer quantum-well lasers

We study the basic physical mechanisms determining the temperature dependence of the threshold current (I-th) Of InP-based strained-layer (SL) quantum-well (QW) lasers emitting at a wavelength of 1.3 mu m. We show that I-th exhibits a different temperature dependence above and below a critical temperature T-c, It is indicated that T-c is the maximum temperature below which the threshold gain exhibits a linear relationship with temperature. We demonstrate that below T-c the Anger recombination current dominates the temperature dependence of I-th. On the other hand, above T-c a significant increase in both the internal loss and radiative recombination current in the separate-confinement-heterostructure region, which is mainly due to electrostatic band-profile deformation, is found to play a major role in determining the temperature sensitivity of I-th. On the basis of the comparison between the theoretical analysis and the experimental results, we conclude that the temperature dependence of the threshold current in 1.3-mu m InP-based SL-QW lasers is dominated by different mechanisms above and below T-c.