Single-mode semiconductor lasers based on quantum-nano-structures for low-power consumption and high functional operations.

GaInAsP/InP应变低维量子结构激光器作为低功耗、高性能的光源，在理论和实验上都得到了广泛的研究。还研究了一种新型的分布反射面(DR)激光器，其制作工艺与量子线激光器和具有线状有源区的分布反馈(DFB)激光器相同。(1)采用电子束光刻、CH_4/H_2反应离子刻蚀和有机金属气相外延两步生长工艺，获得了激活区宽度为30 nm的GaInAsP/InP量子线DFB激光器。对于高台面条纹结构，采用低损伤制作工艺，在…下，当条纹宽度为3.4μm，腔长为350μm时，阈值电流为2.1 mA，对应的阈值电流密度为176A/cm~2，微分量子效率为16%/刻面更多的RT-CW条件。在1542 nm的激光波长下，亚模抑制比(SMSR)高达50d B(偏置电流是阈值的两倍)。(2)为了实现低阈值、高效率和稳定的单模运转，研究了一种由有源DFB和无源DBR量子线结构组成的分布反射面(DR)激光器。利用侧向量子限制效应产生的能量蓝移对DFB和DBR截面进行积分。结果，在RT-CW条件下，获得了低至1.2 mA的阈值电流。实现了前面的最大微分量子效率为36%。此外，利用有源区的深DFB光栅区，实现了DR激光器的亚毫安运转，其折射率耦合系数高达570 cm~(-1)。该器件的最小阈值电流为0.8 mA，阈值电流密度为180A/cm2，前端面的微分量子效率为20%。采用周期为247.5 nm的54 nm量子线有源区增益峰的Bragg波长失谐量，实现了1599 nm GaInAsP/InP类量子线DFB激光器的单模运转和高特性温度运转。实现了单模工作，亚模抑制比(SMSR)高达51dB(RT-CW条件下的偏置电流是阈值的两倍)。实现了在10℃~85℃温度范围内无跳模的固定单模工作。在50℃时，最小阈值电流为5.4 mA，电流密度为520A/cm2。此外，还获得了阈值电流密度和微分量子效率的变化，分别为±19%和24%。较少

GaInAsP/InP strained low dimensional quantum structure lasers have been studied both theoretically and experimentally as the low power consumption, high performance light sources. A new type of distributed reflector (DR) laser, fabricated by the same fabrication processes as those of quantum-wire lasers and distributed feedback (DFB) lasers with wirelike active regions, has also been studied. Results obtained in this research are as follows:(1) A GaInAsP/InP quantum wire DFB laser with the active region width of 30nm in the period of 240nm was realized by an electron beam lithography, CH_4/H_2-reactive ion etching and two-step organometnllic vapor-phase- epitaxial growth processes. By adopting low-damage fabrication processes for high-mesa stripe structures, a threshold current as low as 2.1 mA, which corresponds to a threshold current density of 176 A/cm2, and a differential quantum efficiency of 16%/facet were obtained for the stripe width of 3.4μm and the cavity length of 350μm unde … More r RT-CW condition. A single mode operation with the sub-mode suppression-ratio (SMSR) as high as 50 dB (a bias current of twice the threshold) was also achieved in the lasing wavelength of 1542nm.(2) A distributed reflector (DR) laser, which consists of the active DFB and passive DBR sections with a quantum-wire structure, was studied for the low threshold, high efficiency and stable single-mode operation. The DFB and DBR sections are integrated by using the energy blue shift due to the lateral quantum confinement effect. As a result, a threshold current as low as 1.2mA was obtained under RT-CW conditions. The maximum differential quantum efficiency at the front facet was realized to be 36%. Furthermore a sub-mA operation of a DR laser has been realized with a higher index coupling coefficient of 570 cm^<-1> utilizing a deep DFB grating region in the active section. A minimum threshold current of 0.8mA (threshold current density of 180A/cm^2) and the differential quantum efficiency from the front facet was 20% have been realized. Stable single mode characteristics were preserved with a SMSR value of 41 dB at a bias current of twice threshold current.(3) A single mode operation and a high characteristic temperature operation of 1599nm GaInAsP/InP quantum-wirelike DFB lasers were achieved by adopting the Bragg wavelength detuning from the gain peak of a 54nm quantum wire active regions with a period of 247.5nm. A single mode operation with the sub-mode suppression-ratio (SMSR) as high as 51 dB (a bias current of twice the threshold under RT-CW condition) was achieved. A fixed single-mode operation without a mode hopping over a temperature range between 10℃ and 85℃ was achieved. The minimum threshold current of 5.4mA (current density of 520A/cm^2) was obtained at 50℃. Moreover, the changes of threshold current densities and differential quantum efficiencies as low as±19% and 24%, respectively, were obtained. Less