Low-threshold-current-density 1.5 μm lasers using compressivelystrained InGaAsP quantum wells |
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| Authors: | Osinski J.S. Zou Y. Grodzinski P. Mathur A. Dapkus P.D. |
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| Affiliation: | Dept. of Electr. Eng., Univ. of Southern California, Los Angeles, CA; |
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| Abstract: | A low-threshold current density (Jth) of 140 A/cm2 for broad-area 1.5-μm semiconductor lasers with uncoated facets is demonstrated at a cavity length of 3.5 mm. This was achieved by the use of a single InGaAsP quantum well (QW) of 1.8% compressive strain inside a step-graded InGaAsP waveguide region. Low-cavity losses of 3.5 cm-1 and a relatively wide quantum well as compared to InGaAs wells of equivalent strain contribute to this high performance. Double QW devices of 2 mm length showed threshold current densities of 241 A/cm2. Quaternary single and double QWs of similar width but only 0. 9% strain gave slightly higher threshold current density values, but allowed growth of a 4 QW structure with a Jth of 324 A/cm2 at L=1.5 mm |
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