Fabrication of long-wavelength-range quantum wire lasers

当将量子线应用于垂直腔表面发射激光器（VCSEL）时，期望解决偏振切换的问题，其中偏振方向随着VCSEL的激励电流的增加而改变90度。量子线（QWR）对偏振态沿着量子线方向的光具有优先增益，并使VCSEL输出的激光偏振态稳定。对于1.3-1.55 μm波长范围的VCSEL量子阱激光器，目前还没有文献报道偏振稳定性。我们的项目的目的是开发1.3-1.55 μm范围的QWR，其具有（i）高密度（&gt;3 × 10^5 cm-2<-1>），（ii）高均匀性（PL FWHM&lt;10 meV，20 K），（iii）高横向约束能量（&gt;30 meV），（iv）足够高的光学质量以同时应用于激光二极管，并使用这种高质量量子线实现QWR-VCSEL和QWR条形激光器的室温振荡。经过三年的项目，我们实现了所有最重要的目的。三层 ...更多信息 在<0.53><0.47><0.52><0.48><-1>15 K和300 K下，量子阱的PL半高宽分别为9.7meV和55 meV，量子阱的横向约束能分别为91 meV和55 meV，量子阱的密度分别为4.5× 105 cm ~ 2和4.5× 105 cm ~ 2，量子阱的光学质量通过退火处理得到了很大的改善。结果表明，我们成功地开发了高品质的QWR与四个规格在同一时间。条形接触型激光器在室温下的阈值电流密度<th>为5.3 kA/cm ^3。另一方面，在（775）B InP衬底上生长的1.55 μm范围的量子阱的密度为2.4×10^5 cm^3。<-1>（ii）在300 K下的PL半高宽为44 meV。（iii）层厚调制为3.6-10.8 nm，这意味着足够高的横向约束能。（iv）高的光学质量。只有第一个规范没有得到满足。九个条形接触激光器在室温下产生激光，阈值电流为4.0 kA/cm^3（平均值）和2.8 kA /cm^3（最小值）。量子线的生长速度为2 μm/h，比常规生长速度快2倍，满足了40 μm厚分布布拉格反射镜的制备要求。我们还制备了（775）B GaAs/（AlAs）_1（GaAs）_6和（775）B GaAs/（AlAs）_1（GaAs）_6两种结构的VCSEL，两种结构的VCSEL都显示出室温激光振荡。通过电流激励。对于GaAs QWR VCSEL，激射波长为769 nm，在宽电流范围内的正交偏振抑制比（OPSR）为20 dB。目前还没有文献报道具有GaAs有源层的垂直腔面发射激光器具有如此高的OPSR值。结果表明，（775）B GaAs QWR实现了VCSEL的高偏振稳定性。少

When quantum wires is applied to vertical cavity surface emitting lasers (VCSELs), a problem of polarization switching is expected to be resolved where the polarization direction changes by 90 degrees with increasing the excitation current of VCSELs. Quantum wires (QWRs) have preferential gain for the light with the polarization along the wire direction and stabilize the polarization of the laser light from VCSELs. There is no paper reports the stabilization of polarization for the 1.3-1.55 μm range VCSEL QWRs. The purposes of our project are to develop 1.3-1.55 μm range QWRs with (i)high density (>3 x 10^5 cm^<-1>), (ii)high uniformity (PL FWHM<10 meV at 20 K), (iii)high lateral confinement energy (>30 meV), (iv)enough high optical quality for application to laser diodes at the same time, and to achieve room temperature oscillation of QWR-VCSELs and QWR stripe laser using such high quality quantum wires. After three-years project, we achieved all of most important purposes.Three layer … More s of In_<0.53>Ga_<0.47>As/In_<0.52>Al_<0.48>As QWRs were stacked and they have (i)a density of 4.5×10^5 cm^<-1>, (ii)PL FWHM of 9.7 meV at 15 K,55 meV at 300 K (iii)lateral confinement energy of 91 meV calculation, (iv)much improved optical quality by post-annealing process. The results indicate we have successfully developed high quality QWRs with four specifications at the same time. Stripe contact type laser showed room-temperature lasing at a threshold current density of J_<th>=5.3 kA/cm^3.On the other hand, 1.55-μm range QWRs grown on (775)B InP substrates have a density of 2.4×10^5 cm^<-1> (ii)PL FWHM of 44 meV at 300 K (iii)layer thickness modulation of 3.6-10.8 nm which implies that enough high lateral confinement energy (iv)high optical quality. Only the first specification is not fulfilled. Nine stripe contact lasers show room temperature lasing at a threshold current of 4.0 kA/cm^3 (average), and 2.8 kA /cm^3 (minimum). The quantum wires were grown at a growth rate of 2 μm/h, which is two times faster than the conventional growth rate and necessary for the fabrication of 40 μm thick distributed Bragg reflector. VCSEL with the QWRs lased at 1517 nm at room temperature with a polarization parallel to the wire direction.We also fabricated VCSELs with (775)B GaAs/(AlAs)_1(GaAs)_6 QWRs and with (775)B GaAs/(AlAs)_1(GaAs)_6 QWRs and both VCSELs showed room temperature laser oscillation. by current excitation. For the GaAs QWR VCSEL, the lasing wavelength is 769 nm and orthogonal polarization suppression ratio (OPSR) 20 dB over wide-range of current. There is no paper report the such a high OPSR value for the VCSEL with GaAs active layer. The result indicates that (775)B GaAs QWRs realizes the high stability of polarization of VCSELs. Less