Very high characteristic temperature and constant differential quantum efficiency 1.3-/spl mu/m GaInAsP-InP strained-layer quantum-well lasers by use of temperature dependent reflectivity (TDR) mirror

A very high characteristic temperature T/sub 0/ of 150 K (25-70/spl deg/C) or 450 K (25-50/spl deg/C) and an almost constant differential quantum efficiency operation in the temperature range of 25-70/spl deg/C were achieved in 1.3-/spl mu/m GaInAsP-InP strained-layer quantum-well (SL-QW) lasers by use of a novel temperature dependent reflectivity (TDR) mirror composed of multiple quarter-lambda thickness /spl alpha/-Si-SiOx dielectric films with quarter-lambda shift in the vicinity of center portion, The mechanism of high T/sub 0/ and constant differential quantum efficiency were explained using the structural parameters, transparent current density and gain coefficient of a SL-QW laser that are derived experimentally. The effect of TDR mirror was confirmed by measuring the temperature dependence of net gain of a SL-QW laser with TDR mirror. It was found that less temperature dependent net gain due to the decrease of mirror loss with temperature played an important role for improving the temperature characteristics of threshold current. Almost constant differential quantum efficiency over a wide temperature range is attributed to the increase of the facet reflectivity with temperature.<
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