LOW-THRESHOLD (LESS-THAN-OR-EQUAL-TO-92 A/CM2) 1.6 MU-M STRAINED-LAYER SINGLE QUANTUM-WELL LASER-DIODES OPTICALLY PUMPED BY A 0.8 MU-M LASER DIODE

To explore the ultimate threshold current limit in long-wavelength semiconductor lasers, InxGa1-xAs/InP strained-layer single quantum well laser diodes were studied for the first time by optically pumping with a 0.8 μm laser diode. Low-threshold (≤92 A/cm2) cw operation was obtained and the lasing wavelength (1.62 μm) corresponding to the transition from the first quantization state of a 25 Å In 0.8Ga0.2As well was observed. By taking the carrier collection efficiency (≤77%) into account, the actual threshold current density could be as low as 70 A/cm2.