An Electroabsorption Modulator Monolithically Integrated with a Semiconductor Optical Amplifier and a Dual-Waveguide Spot-Size Converter

A semiconductor optical amplifier and electroabsorption modulator monolithically integrated with a spot-size converter input and output is fabricated by means of selective area growth,quantum well intermixing,and asymmetric twin waveguide technology.A 1550～1600nm lossless operation with a high DC extinction ratio of 25dB and more than 10GHz 3dB bandwidth are successfully achieved.The output beam divergence angles of the device in the horizontal and vertical directions are as small as 7.3°×18.0°,respectively,resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.     

半导体激光器电吸收调制器和双波导模斑转换器的单片集成

报道了1.6μm的半导体激光器和电吸收调制器以及双波导模斑转换器的单片集成器件.该器件具有良好的单横模特性和准单纵模特性(边模抑制比达25.6dB),3dB调制带宽为15GHz,直流消光比为16.2dB,远场发散角为7.3°×18.0°,和单模光纤的耦合效率达3.0dB.     

Monolithically Integrated Laser Diode and Electroabsorption Modulator with Dual- Waveguide Spot-Size Converter Output

A 1.60μm laser diode and electroabsorption modulator monolithically integrated with a novel dual-waveguide spot-size converter output for low-loss coupling to a cleaved single-mode optical fiber are demonstrated.The devices emit in a single transverse and quasi single longitudinal mode with an SMSR of 25.6dB.These devices exhibit a 3dB modulation bandwidth of 15.0GHz,and modulator DC extinction ratios of 16.2dB.The output beam divergence angles of the spot-size converter in the horizontal and vertical directions are as small as 7.3°×18.0°,respectively,resulting in a 3.0dB coupling loss with a cleaved single-mode optical fiber.     

A simple and elegant technique connecting Marcuse spot size relations to variational formulations in single-mode fiber characterization

Accurate knowledge of spot size, an important criterion in single-mode fiber optics, is obtained by two different optimization techniques, the well-known variational method and Marcuse formulation. The later is more accurate but cannot predict fiber parameters from given spot sizes. In this study, it is shown for the first time to the best of our knowledge that using simultaneously Marcuse relations of fiber spot sizes for single-mode graded index fibers and also variational formulation, we can more accurately and easily determine the fiber parameters for a particular normalized frequency. Then it is shown with typical example of fractional power in the core that in the case of such fibers, this synthesis of these two useful approaches can also more accurately estimate propagation characteristics of practical interest. This equivalence provides an easy and useful connection between two fundamental but disjoint approaches and should find wide use.     

使用传统工艺实现1.55μm激光器与模斑转换器的单片集成

采用传统的光刻和湿法腐蚀工艺制作了1.55μm波长的新型半导体激光器和模斑转换器的单片集成器件.其中激光器采用脊型双波导,模斑转换器采用掩埋双波导结构,水平楔型的有源波导和宽而薄的无源波导同时控制光斑模式大小.实验测得器件的阈值电流为40mA,斜率效率为0.35W/A,水平和垂直方向的远场发散角分别为14.89°和18.18°,与单模光纤的耦合损耗为3dB.     

硅基波导用楔形模斑变换器的研究进展

楔形模斑变换器在利用硅基光子集成技术实现芯片间光互连中有着广泛的应用.文章概述了国内外楔形模斑变换器的最新研究进展.介绍了几种新型模斑变换器的结构及制作的工艺流程,并对其性能及影响楔形模斑变换器耦合效率的几个因素进行了分析比较,进而讨论了这几种模斑变换器存在的问题及进一步提高耦合效率的可能性.     

电吸收调制器与半导体光放大器和双波导模斑转换器的单片集成

采用选择区域生长、量子阱混杂和非对称双波导技术制作了电吸收调制器与半导体光放大器和双波导模斑转换器的单片集成器件.器件在波长1.55～1.60μm范围内,3dB带宽大于10GHz,直流消光比为25dB,插入损耗小于0dB,远场发散角为7.3°×18.0°,与单模光纤的耦合效率达3.0dB.     

有双包层结构的楔变脊型光斑转换器的设计

为了提高硅基上单模波导器件与单模光纤的耦合效率和工艺容差,设计了一种实用新型光斑转换器,它由水平和垂直双向楔变的波导芯区和双内包层构成.分析了内包层折射率与其厚度对耦合效率的影响,发现通过优化内包层的参数可以加强对扩展光场的限制.针对在硅基上制作垂直楔变结构的波导还很困难的情况,提出了一种低成本、简单可行的制作方法.     

Simulation of structural design with high coupling efficiency in external cavity semiconductor laser

For external cavity semiconductor lasers(ECSLs),high coupling efficiency is critical to reducing the linewidth.In this paper,the coupling efficiency between the laser diode and the waveguide grating has been improved,with proposals for its improvement presented,including adding spot-size conversion(SSC)and using a silicon-on-insulator(SOI)waveguide.The results indicate an increase of coupling efficiency from 41.5%to 93.1%,which exhibits an improvement of approximately 51.6%over conventional schemes.The relationship between coupling efficiency and SOI waveguide structures is mainly concerned in this article.These findings provide a new way for the future research of the narrow linewidth of ECSL.     

应用于Ⅲ-Ⅴ族半导体光调制器的模斑变换器设计

半导体光调制器波导的输出模斑通常是直径为2～3μm的椭圆形,与光纤进行耦合时会因模斑不匹配而产生严重的耦合损耗,并影响对准容差.为降低光纤与调制器波导的耦合损耗,同时改善对准容差,设计了两种应用于光调制器中的模斑变换器(Spot-size Converter),通过仿真对其传输损耗和模场耦合效率进行了比较,其中采用混合结构的模斑变换器具有更优的性能.