小像元量子阱FPA抗光学串音的FDTD仿真

FDTD Simulation of the Performance on Anti-optical Crosstalk of Small Pixel Quantum Well Focal Plane Array

摘要:

采用光栅耦合结构的焦平面阵列(Focal Plane Array,FPA)在工艺上难以制备,反射耦合结构较为容易。为探究反射耦合结构是否可以在小尺寸范围内替代光栅耦合结构,文章使用FDTD电磁场仿真软件MEEP构建了光栅耦合结构和反射结构GaAs/AlGaAs量子阱红外焦平面阵列三像元模。通过对器件内部光学串音进行仿真,验证了在逼近衍射极限时,采用全内反射结构的FPA在5~7μm和8.5~10μm之间的抗串音效果强于光栅耦合结构,而在6.5~8.5μm和10~12μm之间,光栅耦合结构的抗串音效果更好,在12~15μm范围内,两种结构的抗串音能力相当。针对15μm中心距全内反射结构量子阱FPA,探究了反射角度、刻蚀深度和量子阱周期对其串音的影响。

Abstract:

Quantum well FPA with reflection coupling structure is relatively easy to fabricate compared with the grating coupling structure. In order to explore whether the RC structure could replace the GC structure in the small size range, the MEEP, a software which is based on the FDTD, was used to construct the 3pixels model of GC structure and RC structure GaAs/AlGaAs quantum well infrared FPA. According to the simulation of the internal optical crosstalk problem of the device, it is verified that when approaching the diffraction limit, the anti-crosstalk effect of FPA with RC structure is stronger than that of RC structure when the pixel’s size is between 5~7μm and 8.5~10μm, while GC shows better performance while the pixel’s size is between 7~8.5μm and 10~12μm, and the anti-crosstalk ability of the two structures shows close performance in the range of 12~15μm. For the quantum well FPA with 15μm pixels and RC structure, the influence of reflection angle, etch depth and the period of quantum well on its performance of fighting against the crosstalk was explored.