A novel approach for achieving ultrafast and wide tunable vertical-cavity surface-emitting lasers (VCSELs) is presented. The design is based on incorporating multiple graphene flakes separated by SiO 2 dielectric in a λ/2 cavity and placing multiquantum wells in one of the quarter wave layers of the bottom mirrors. The device concept enhances both the wavelength tuning range and tuning speed which is attractive for many photonic applications. By applying a gate voltage on the graphene flakes, the effective refractive index of the cavity can be changed with ultrahigh speed. We have shown that 2 graphene flakes inside a 5 µm-diameter passive cavity provides tuning speed as high as 32 GHz and wavelength tuning range of 3.8 nm. The tuning speed increases to 52 GHz when the device diameter is reduced to 3 µm. The effect of spacer thickness and the number of graphene flakes on the performance characteristics of the device is investigated. Our analysis shows that tuning speed as high as 2 GHz and wavelength tuning range of ~ 12 nm is obtained for VCSEL that incorporates 6 graphene flakes separated by 10 nm SiO 2 spacers and biased in parallel. The tuning speed can be increased to ~ 16 GHz when the flakes are biased in series at the expense of higher gate voltage. A tradeoff between the wavelength tuning range and the tuning speed is obtained.

中文翻译：

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使用石墨烯无源腔的超快宽可调 VCSEL

提出了一种实现超快和宽可调谐垂直腔面发射激光器 (VCSEL) 的新方法。该设计基于在 λ/2 腔中加入由 SiO 2 电介质分隔的多个石墨烯薄片，并在底部反射镜的四分之一波长层之一中放置多量子阱。该器件概念增强了波长调谐范围和调谐速度，这对许多光子应用具有吸引力。通过在石墨烯薄片上施加栅极电压，可以超高速改变腔体的有效折射率。我们已经证明，直径为 5 µm 的无源腔内的 2 个石墨烯薄片可提供高达 32 GHz 的调谐速度和 3.8 nm 的波长调谐范围。当器件直径减小到 3 µm 时，调谐速度增加到 52 GHz。研究了间隔物厚度和石墨烯薄片数量对器件性能特性的影响。我们的分析表明，VCSEL 获得了高达 2 GHz 的调谐速度和 ~ 12 nm 的波长调谐范围，该 VCSEL 包含 6 个石墨烯薄片，由 10 nm SiO 2 间隔物分隔并平行偏置。当薄片以更高的栅极电压为代价串联偏置时，调谐速度可以增加到 ~ 16 GHz。获得了波长调谐范围和调谐速度之间的折衷。当薄片以更高的栅极电压为代价串联偏置时，调谐速度可以增加到 ~ 16 GHz。获得了波长调谐范围和调谐速度之间的折衷。当薄片以更高的栅极电压为代价串联偏置时，调谐速度可以增加到 ~ 16 GHz。获得了波长调谐范围和调谐速度之间的折衷。