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 dep endence of the threshold current (I-th) Of InP-based strained-layer (S L) quantum-well (QW) lasers emitting at a wavelength of 1.3 mu m. We s how that I-th exhibits a different temperature dependence above and be low a critical temperature T-c, It is indicated that T-c is the maximu m temperature below which the threshold gain exhibits a linear relatio nship with temperature. We demonstrate that below T-c the Anger recomb ination current dominates the temperature dependence of I-th. On the o ther hand, above T-c a significant increase in both the internal loss and radiative recombination current in the separate-confinement-hetero structure region, which is mainly due to electrostatic band-profile de formation, is found to play a major role in determining the temperatur e sensitivity of I-th. On the basis of the comparison between the theo retical analysis and the experimental results, we conclude that the te mperature 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.