Temperature dependence of the threshold current in gain-coupled distributed feedback lasers with periodically etched quantum wells: Mechanism for an appearance of infinite T-0

A phenomenological model describing the temperature dependence of the threshold current of 1.3 mu m gain-coupled distributed feedback (DFB) lasers with periodically etched strained-layer quantum wells is presented and compared to experimental results. The model can predict the minimum threshold current as a function of temperature (infinite T-0), which has been observed experimentally. The mechanism for the appearance of this minimum is explained by the decrease of the detuning of the DFB-mode wavelength from the material gain-peak wavelength as the temperature increases. The condition for single-mode operation is also discussed with use of the effective gain of DFB laser structures. (C) 1996 American Institute of Physics.