Development of High Performance Distributed Feedback Semiconductor Lasers for Short Wavelength Region

1.将调制条纹宽度结构应用于短波区域分布反馈（DFB）激光器，实现了DFB激光器的单纵模完全振荡。这种结构是通过采用一种新的复合半导体反应离子蚀刻（RIE）技术实现的。同时介绍了几种制备衍射光栅的新技术，包括利用RIE将光栅图案转移到外延层上。结果大大改善了光栅的齿形。据我们所知，这样制作的装置是第一个没有湿蚀刻完成的埋式异质结构DFB激光器。接下来，我们开发了一个精确的器件模拟器，以研究纵向空间孔燃烧对这种相移DFB激光器特性的确切影响。根据计算结果，我们设计了适当的条纹形状，以减少更多的波长啁啾，从而最大限度地减少这种影响。可见光DFB激光器根据我们开发高性能0.88 m DFB激光器的经验，我们下一步尝试进一步减少振荡波长。通过对制作工艺的改进和改进，我们成功地获得了DFB在可见光波段的振荡。=770nm)在我们简单的氧化条器件中。振荡波长对温度的依赖性为0.054nm/K，在超过50k的温度范围内无模跳变现象。本文首次在半导体DFB激光器中引入了增益耦合机制，并证明了其在完全单模纵模振荡中的适用性。我们还发现，这种DFB激光器的激光特性几乎不受面反射的影响，这与传统的DFB激光器形成了鲜明的对比。这个特性是人们一直迫切要求但从未实现的。研究了0.88 m DFB激光器与光调制器/放大器的单片集成。由于在这类集成器件中，元件器件之间的光学隔离至关重要，因此我们首先通过对振荡和调制特性进行数值分析来估计前面的最大可容忍反射率。原型装置的制造已经完成。少

1.DFB Laser with Modulated Stripe Width structure We applied the modulated stripe width structure to short wavelength region distributed feedback (DFB) lasers for achieving complete single longitudinal mode oscillation in them. This structure was made possible by employing a novel reactive ion etching (RIE) technigue for composite xemiconductors. At the same time several new techniques were introduced for the fabrication of diffraction grationgs, including the use of RIE for transferring the grating patterns onto the epitaxial layers. AS a result the tooth shape of the grating was greatly improved. To our knowledge the device thus fabricated was the first buried heterostructure DFB laser completed without wet etching. Next we developed an accurate device simulator in order to investigate the exact effect of longitudinal spatial hole burning on the characteristics of this kind of phase-shifted DFB laser. From the calculated results we designed appropriate stripe shapes for reducing the … More wavelength chirping as a consequence of minimizing that effect.2. Visible Light DFB Laser On our experience of having developed high performance 0.88 m DFB lasers, we next tried further reduction of oscillation wavelength. By modifying and improving the fabrication processes, we succeeded in obtaining DFB oscillation in visible wavelength region(【.Ibdabar.】=770nm) in our simple oxide stripe devices. Temperature dependence of oscillation wavelength was 0.054nm/K, and mode hopping was not observed within temperature range over 50K.3. DFB Laser with Gain Coupling Mechanism We for the first time introduced the gain coupling mechanism to the semiconductor DFB laser, and showed its usefulness for complete single longitudinal mode oscillation. We also found out that the lasing characteristics of a DFB laser of this kind are almost immune to facet reflection, which made a striking contrast with the conventional DFB lasers. This feature is the one that has been eagerly demanded but never realized.4. DFB Laser monolithically integrated with Optical Modulator/Amplifier Monolithic integration of a 0.88 m DFB laser and an optical modulator/amplifier was examined. Since, in integrated devices of this sort, optical isolation between element devices is essentially important, we first estimated the maxinum tolerable reflectivity at the front facet by carrying out numerical analysis of the osdillation and modulation characteristics. Fabrication of a prototype device has been completed. Less