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中红外光电器件在传感与成像等领域具有重要且广泛的应用,目前相关的光学系统往往由分立的器件组成,将这些体积庞大的光学系统集成到一块芯片上是光子集成研究的长期目标,近些年,国内外许多研究团队报道了中红外片上传感和片上成像方面的研究成果,但是这些研究基本都通过将外置光源的输出耦合进入芯片来实现片上功能,激光光源实际上并没有在片上集成,实现激光器的光子集成是实现真正的片上传感和片上成像的重要一步。另外一方面,光子集成平台可以提供低损耗的光波导、宽调谐的滤波器、高品质因子的微环谐振器,将III-V族半导体激光器与这些元件集成到一起可以实现传统中红外半导体激光平台难以实现的宽调谐、窄线宽等先进功能。文中详细介绍了近些年中红外QCL光子集成的研究进展,表1展示了不同光子集成方式之间的对比。目前片上集成的QCL在性能方面与传统III-V衬底上的器件还有较大差距,这一方面是因为异质集成增加了器件的工艺难度,同时QCL与无源波导之间的较差的耦合效率也使得器件的性能不如预期,此外片上集成也增加了QCL器件的散热难度。在后续的研究中,需要优化QCL与无源波导的耦合结构,研究实现QCL高效片上散热的方法,探索硅上外延生长的新途径,实现QCL与光子芯片的晶圆集成,使完全集成的中红外光子传感器成为现实。
Integration
approachIntegration
densityActive-passive
couplingHeat dissipation Process yield Current
performanceDetector
integrationMonolithic integration on InP ★★★ ★★★ ★★★ ★★★ ★★ ★★ Monolithic integration on Silicon ★★★ − ★★ ★ ★ ★★ Heterogeneous integration on silicon ★★★ ★★ ★★ ★★ ★ ★ Hybrid external cavity ★ ★ ★★★ ★★★ ★ − Table 1. Comparison of different photonic integration approaches for mid-infrared QCLs
Photonics integration of mid-infrared quantum cascade laser (Invited)
doi: 10.3788/IRLA20220197
- Received Date: 2022-03-17
- Rev Recd Date: 2022-03-23
- Publish Date: 2022-04-07
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Key words:
- quantum cascade laser /
- photonics integration /
- mid-infrared /
- silicon photonics /
- optical sensing
Abstract: Mid-infrared photonic integrated circuits have been attracting a lot of interest for applications in environmental monitoring, medical diagnosis and national defense. However, the integration of laser sources with low-loss mid-infrared waveguide circuits is challenging. Quantum cascade lasers (QCLs) are important semiconductor laser sources operating in the mid-infrared spectral range. In this review paper, the research progress of the photonics integration of mid-infrared QCLs in recent years was introduced. Several different approaches were reviewed, including monolithic integration on InP, monolithic integration on silicon, heterogeneous integration on silicon and III-V/Germanium hybrid external cavity laser.