THEORETICAL COMPARISON OF TENSILE STRAINED InGaAs/InAlGaAs AND InGaAs/InGaAsP QW LASERS EMITTING AT 1.55 ?M

Abstract

0.78% and 1% tensile strained InGaAs/InAlGaAs and InGaAs/InGaAsP QW lasers. For a small barrier band gap (small band discontinuity), a small number of subbands and a lower density of states result. Thus, the optical gain and T0 are higher. However, the 3 dB bandwidth is reduced by 40 - 50% at 350K with respect to that of 290K. InGaAs/InGaAsP QW lasers (0.78% tensile strained, barrier band gap= 0.94 eV) can achieve a threshold of 364 Acm·2 a 3 dB bandwidth of 20 GHz and To of 60K at a gain of 100 cm·1. InGaAs/InAIGaAs QW lasers (0.78% tensile strained, barrier band gap=0.87 eV) can achieve a threshold of 439 Acm-2 , a 3 dB bandwidth of 15 GHz and T0 of 97K. To conclude, InGaAs/lnAIGaAs laser, due to its large conduction band offset ratio, could be designed to give a low threshold, a large bandwidth and low T0.