Structural design of mid-infrared waveguide detectors based on InAs/GaAsSb superlattice

基于InAs/GaAsSb超晶格的中红外波导探测器结构设计

In the realm of near-infrared spectroscopy,the detection of molecules has been achieved using on-chip waveguides and resonators.In the mid-infrared band,the integration and sensitivity of chemical sensing chips are often constrained by the reliance on off-chip light sources and detectors.In this study,we demonstrate an InAs/GaAsSb superlattice mid-infrared waveguide integrated detector.The GaAsSb waveguide layer and the InAs/GaAsSb superlattice absorbing layer are connected through evanescent coupling,facilitating efficient and highquality detection of mid-infrared light with minimal loss.We conducted a simulation to analyze the photoelectric characteristics of the device.Additionally,we investigated the factors that affect the integration of the InAs/GaAs⁃Sb superlattice photodetector and the GaAsSb waveguide.Optimal thicknesses and lengths for the absorption lay⁃er are determined.When the absorption layer has a thickness of 0.3μm and a length of 50μm,the noise equiva⁃lent power reaches its minimum value,and the quantum efficiency can achieve a value of 68.9%.The utilization of waveguide detectors constructed with Ⅲ-Ⅴ materials offers a more convenient means of integrating mid-infra⁃red light sources and achieving photoelectric detection chips.

InAs/GaAsSb超晶格;波导探测器;倏逝波耦合;GaAsSb波导中文摘要:在近红外领域,已经利用片上波导和谐振器实现了分子的光谱检测。然而在中红外波段,许多传感器仍使用芯片外光源和探测器,这限制了化学传感芯片的集成度和灵敏度。本文设计了一种InAs/GaAsSb超晶格中红外波导集成探测器,采用GaAsSb作为中红外波导,波导层和InAs/GaAsSb超晶格吸收层之间采用倏逝波耦合方式,可以实现低损耗和高响应度的中红外光探测。对器件的光电特性进行了模拟,着重分析了InAs/GaAsSb超晶格光电探测器与GaAsSb波导集成的影响因素,得到了吸收区的最优厚度和长度。当吸收区的厚度为0.3μm、长度为50μm时,噪声等效功率最低,量子效率可以达到68.9%。基于Ⅲ-Ⅴ族材料的波导探测器更容易集成中红外光源,实现中红外的片上集成光电检测芯片。