1.5 MU-M WAVELENGTH COMPRESSIVELY STRAINED GAINAS ALGAINAS MULTI-QUANTUM-WELL LASERS GROWN BY MOLECULAR-BEAM EPITAXY WITH HIGH DIFFERENTIALGAIN AND LOW-THRESHOLD CURRENT-DENSITY/

1.5 mu m GaInAs/AlCaInAs multiquantum-well (MQW) lasers with 1% compre ssively strained quantum wells were grown by molecular-beam epitaxy. T he effective differential gain (g(0)) determined from the squared rela xation oscillation frequency versus output power relations is a high v alue of 9.3x10(-16) cm(2) in long-wavelength lasers. On the other hand , the effective transparent carrier density (n(0)) of strained-layer M QW lasers determined from the measurement of the spontaneous carrier l ifetime was found to be very high, which is different from the theory of strain effects. However, by taking the carrier transport effect int o account, it was shown that (1) for the strained MQW lasers the intri nsic transparent carrier density is lower than that of the lattice-mat ched MQW lasers, and (2) the intrinsic value of g(0) is estimated to b e 28-56x10(-16) cm(2), which is close to the theoretically predicted v alue. By improving the laser structure to have better carrier transpor t, much higher effective differential gain and lower effective transpa rent carrier density can be expected. (C) 1995 American Institute of P hysics.