Effects of well number on temperature characteristics in 1.3-μm AlGaInAs-InP quantum-well lasers

Abstract

Effects of well number on temperature characteristics have been investigated in 1.3-/spl mu/m AlGaInAs-InP compressively strained multiple-quantum-well lasers. Well-number dependence of threshold currents (I/sub th/), external quantum efficiencies (/spl eta//sub d/), characteristic temperatures of I/sub th/ and /spl eta//sub d/ arid maximum operation temperatures have been experimentally determined and analyzed. The characteristic temperature of the threshold current (T/sub 0/) and the maximum operation temperature (T/sub max/) were found to increase with increasing the number of quantum wells and a record high pulsed T/sub max/ of 220/spl deg/C has been achieved in lasers with ten wells. In contrast, the characteristic temperature of the external efficiency (T/sub /spl eta//) was found to decrease with increasing the number of wells. Because of this opposite well-number dependence of the T/sub 0/ and T/sub /spl eta//, each of them alone is not necessarily a good measure to optimize the number of wells. Therefore, in this work, me also evaluated a power reduction at a constant current with increasing temperature, which depends on both T/sub 0/ and T/sub /spl eta// and thus should be a more practical measure of the temperature characteristics, and discuss the optimum number of the quantum wells.