Low-threshold-current and high-temperature operation of 1.3 mum wavelength AlGaInAs/AlGaInAs strain-compensated multiple-quantum-well laser diodes (LDs) with a linearly graded index separate confinement heterostructure also made up of AlGalnAs has been successfully fabricated. The threshold current density and differential quantum efficiency are 400 A/cm(2) and 22% for the as-cleaved broad-area LDs with a 900 pm cavity length, respectively. The calculated internal quantum efficiency, internal optical loss, and threshold gain are 23%, 6.5 cm(-1), and 45 cm(-1), respectively. The threshold current and slope efficiency at room temperature for the 3 mum-ridge-stripe LDs without facet coating are 12 mA and 0.17 W/A, respectively. The peak wavelength is at 1295 nm with an injection current of 60 mA. With increasing the temperature up to 100 degreesC, the threshold current will increase up to 41 mA. The characteristic temperature is around 78 K in the range from 20 to 60 degreesC and 56 K in the range from 60 to 100 degreesC. The wavelength swing varied with temperature is 0.43 nm/degreesC for the LDs operated at 60 mA and room temperature. (C) 2002 Elsevier Science Ltd. All rights reserved.