Carrier capture time and its effect on the efficiency of quantum-well lasers

Carrier capture time of the quantum well, which is an important parameter in the laser operation, was estimated for separate-confinement-heterostructure single-quantum-well (SCH-SQW) lasers by measuring the spontaneous emission from the optical confinement layers, which increases with current even above the laser threshold due to finite capture time. By fitting theoretical analysis to the measurement, hole capture time was found to be the dominant factor for the spontaneous emission increase, and was estimated to be 0.2-0.3 ps for GaInAs/GaInAsP/InP step- and graded-refractive-index-(GRIN-) SCH-SQW lasers, independent of the optical confinement structures. The same measurement was done for multiquantum-well lasers, and it was found that transport across the barrier was also responsible for the spontaneous emission increase and inhomogeneous injection into each well. The effect of the hole capture time and the transport time on the threshold current and the quantum efficiency was analyzed for high-power operation, considering the absorption loss by the carriers in the optical confinement layers. GRIN-SCH structure is shown to keep high differential efficiency in high-power operation in comparison with step-SCH structures, because the carrier density in the confinement layer is small and increases very little above threshold. >

[1]  W. Rideout,et al.  Well-barrier hole burning in quantum well lasers , 1991, IEEE Photonics Technology Letters.

[2]  P. Blood,et al.  Measurement and calculation of spontaneous recombination current and optical gain in GaAs-AlGaAs quantum-well structures , 1991 .

[3]  H. Hirayama,et al.  Estimation of carrier capture time of quantum‐well lasers by spontaneous emission spectra , 1992 .

[4]  U. Koren,et al.  Nonequilibrium effects in quantum well lasers , 1992 .

[5]  Masahiro Asada,et al.  Density-matrix theory of semiconductor lasers with relaxation broadening model-gain and gain-suppression in semiconductor lasers , 1985 .

[6]  Scott W. Corzine,et al.  Effects of carrier transport on high‐speed quantum well lasers , 1991 .

[7]  U. Koren,et al.  Ultrafast gain dynamics in 1.5 μm multiple quantum well optical amplifiers , 1991 .

[8]  A. Adams,et al.  Background carrier concentration and electron mobility in LPE In1−xGaxAsyP1−y layers , 1979 .

[9]  J. P. Hirtz,et al.  The carrier mobilities in Ga0.47In0.53as grown by organo-mettalic CVD and liquid-phase epitaxy , 1981 .

[10]  J. Hayes,et al.  Mobility of holes in the quaternary alloy In 1-x Ga x As y P 1-y , 1980 .

[11]  Kurz,et al.  Dynamics of carrier transport and carrier capture in In1-xGaxAs/InP heterostructures. , 1992, Physical review. B, Condensed matter.

[12]  Benoit Deveaud,et al.  Capture of photoexcited carriers in a single quantum well with different confinement structures , 1991 .

[13]  T. C. Damen,et al.  Capture of electrons and holes in quantum wells , 1988 .

[14]  Masahiro Asada,et al.  Analysis of current injection efficiency of separate-confinement-heterostructure quantum-film lasers , 1992 .

[15]  C. Harder,et al.  Carrier heating in ALGaAs single quantum well laser diodes , 1991 .

[16]  G. Eisenstein,et al.  Structure dependent modulation responses in quantum-well lasers , 1992 .

[17]  Measurements of the barrier‐well injection bottleneck in a multiple quantum well optical amplifier , 1992 .