Fabrication of long-wavelength-range quantum wire lasers

将量子线应用于垂直腔面发射激光器（VCSELs）中，有望解决极化方向随激发电流增加而发生90度变化的问题。量子线对沿线方向偏振的光具有优先增益，稳定了来自vcsel的激光偏振。1.3 ~ 1.55 μm范围VCSEL量子水阱的偏振稳定尚未见文献报道。我们项目的目的是开发1.3-1.55 μm范围的QWR，具有(i)高密度（bbb3 × 10^5 cm^<-1>）， （ii）高均匀性（20 K时PL FWHM<10 meV）， （iii）高侧向约束能量（>30 meV）， （iv）足够高的光学质量，可以同时应用于激光二极管，并使用这种高质量的量子线实现QWR- vcsels和QWR条纹激光器的室温振荡。经过三年的项目，我们达到了所有最重要的目的。通过三层叠加，获得了In_<0.53>Ga_<0.47>As/In_<0.52>Al_<0.48>As的qws (i)密度为4.5×10^5 cm^<-1>, (ii) 15 K时的PL FWHM为9.7 meV， 300 K时为55 meV （iii）计算的侧限能为91 meV， （iv）经退火处理后光学质量大大提高。结果表明，我们成功地同时开发了四种规格的高质量qwr。条形接触式激光器在阈值电流密度为J_<th>=5.3 kA/cm^3的条件下可实现室温激光。另一方面，在（775）B InP衬底上生长的1.55 μm范围qws的密度为2.4×10^5 cm^<-1> (ii)在300 K下的PL FWHM为44 meV （iii）层厚度调制为3.6-10.8 nm，这意味着具有足够高的侧向约束能量（iv）高的光学质量。只有第一个规范没有实现。九条形接触激光器显示室温激光阈值电流为4.0 kA/cm^3（平均）和2.8 kA/cm^3（最小）。该量子线的生长速度为2 μm/h，比传统的生长速度快2倍，是制作40 μm厚的分布式Bragg反射器所必需的。在1517 nm的波长下，在室温下，偏振方向平行于线材方向。我们还用（775）B GaAs/(AlAs)_1(GaAs)_6 qws和（775）B GaAs/(AlAs)_1(GaAs)_6 qws制备了VCSELs，两种VCSELs都表现出室温激光振荡。通过电流激励。对于GaAs QWR VCSEL，在宽电流范围内，激光波长为769 nm，正交偏振抑制比（OPSR）为20 dB。有GaAs有源层的VCSEL有如此高的OPSR值，目前尚无文献报道。结果表明，（775）B GaAs qws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