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Study of microcavity semiconductor laser which allows the quantum optical confinement by vertical multiple reflectors

垂直多重反射镜量子光学约束微腔半导体激光器的研究

基本信息

批准号：
07837004
负责人：
BABA Toshihiko
金额：
$ 1.41万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07837004/
关键词：
semiconductor laser reflector GaInAsP InP optical communication short cavity reactive ion beam etching photonic integration 加入者系光通信光インターコネクト DBR

项目摘要

Next era optical fiber communications such as FTTH and optical interconnect require a semiconductor laser that enables the low power consumption, high efficiency and adaptability to mass production. In this study, a novel monolithic short cavity laser simultaneously satisfying these requirements was proposed and demonstrated. This laser has vertical multiple reflectors. Since this type of reflector is equivalent to the multilayr mirror with semiconductor and air, it achieves a high reflectivity over 0.99 even with a small number of pairs. Thus it allows the extreme short cavity, resulting in the ultra-low threshold. It has been shown theoretically that, when we assume GaInAsP/InP compressive strained quantum wells as the active layr, threshold current as low as 100muA will be possible with cavity length of 20mum and stripe width of 1mum. To fabricate this type of reflector, we optimized the condition of electron beam lithography and that of reactive ion beam etching (RIBE). It realized … More the semiconductor linewidth of 0.3mum in the multiple reflector, which corresponds the condition of the third diffractional grating. We observed the threshold current normalized by stripe width of 2.6mA/mum for dabricated laser with the refractor for one end and cavity length of 100mum. The comparison between the experiment and theoretical estimation of threshold current indicates that the effective reflectivity of the reflector in the fabricated device was nearly 0.6. This is slightly lower than the theoretical value obtained by taking the diffraction loss into account. It seems to be caused by the roughness of semiconductor sidewalls induced during the etching process. It was measured to be 20 nm from the topographic image by a multi-dimensional scanning electron micrograph. We have also observed that the increase of the number of semiconductor walls simply improves the threshold current. Theoretically it was found that (1) diffraction loss is reduced and effective reflectivity is increased to over 0.95 by changing the air space between semiconductor walls from the third order grating design to the first order, and (2) the first order design for both semiconductor linewidth and air space provides relatively small improvements to the effective reflectivity. However, the air space of the first order design requires the extremely fine etching condition. The trial fabrication of the air space by the RIBE etching concluded that the increase of acceleration voltage of ion beam allows upto the second order design but does not the first order design. We expect the following research to realize the first order design and drastically improve the laser performance by introducing the chemically assisted ion beam etching, which exhibits the smooth semiconductor sidewalls and high aspect ratio. It will not only contribute to the laser performance but also to the integration technology of laser and other photonic devices such as detectors and modulators. Less

光纤到户、光互连等下一代光纤通信需要低功耗、高效率、适应量产的半导体激光器。在本研究中，提出并演示了一种同时满足这些要求的新型单片短腔激光器。这种激光器有垂直的多重反射器。由于这种类型的反射镜相当于由半导体和空气组成的多层反射镜，因此即使使用少量对，其反射率也能达到0.99以上。因此它允许极短的空腔，从而产生超低的阈值。理论表明，当我们假设GaInAsP/InP压缩应变量子阱作为有源层时，当腔长为20mum，条带宽度为1mum时，阈值电流可能低至100muA。为了制作这种类型的反射器，我们优化了电子束光刻和反应离子束蚀刻（RIBE）的条件。在多重反射镜中实现了半导体线宽0.3 μ m，符合第三衍射光栅的条件。我们观察到一端为折射器、腔长为100mum的激光，其阈值电流归一化后的条纹宽度为2.6mA/mum。实验结果与理论估计的阈值电流的比较表明，该装置中反射器的有效反射率接近0.6。这比考虑衍射损失后得到的理论值略低。这似乎是由于在蚀刻过程中引起的半导体侧壁粗糙度引起的。通过多维扫描电子显微图测量其距离地形图20 nm。我们还观察到，半导体壁数的增加只是提高了阈值电流。理论上发现：(1)通过改变半导体壁间的空气空间，从三阶光栅设计到一阶光栅设计，可以减少衍射损失，提高有效反射率到0.95以上；(2)一阶设计对半导体线宽和空气空间的有效反射率的改善相对较小。然而，一阶设计的空气空间要求极其精细的蚀刻条件。利用RIBE刻蚀法对空气空间进行了试验，结果表明，离子束加速电压的增加可以达到二阶设计，但不能达到一阶设计。我们期望在接下来的研究中，通过引入化学辅助离子束刻蚀，实现一阶设计，并大幅提高激光器的性能，使其具有光滑的半导体侧壁和高宽高比。它不仅有助于提高激光器的性能，而且有助于激光器与其他光子器件如探测器和调制器的集成技术。少