Space-to-ground high-speed transmission is of utmost importance for the development of a worldwide broadband network. Mid-infrared wavelengths offer numerous advantages for building such a system, spanning from low atmospheric attenuation to eye-safe operation and resistance to inclement weather conditions. We demonstrate a full interband cascade system for high-speed transmission around a wavelength of 4.18 µm$4.18\mathrm{\mu }\mathrm{m}$. The low-power consumption of both the laser and the detector in combination with a large modulation bandwidth and sufficient output power makes this technology ideal for a free-space optical communication application. Our proof-of-concept experiment employs a radio-frequency optimized Fabry–Perot interband cascade laser and an interband cascade infrared photodetector based on a type-II InAs/GaSb superlattice. The bandwidth of the system is evaluated to be around 1.5 GHz. It allows us to achieve data rates of 12 Gbit/s with an on–off keying scheme and 14 Gbit/s with a 4-level pulse amplitude modulation scheme. The quality of the transmission is enhanced by conventional pre- and post-processing in order to be compatible with standard error-code correction.

中文翻译：

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用于节能中红外自由空间通信的带间级联技术

天地高速传输对于全球宽带网络的发展至关重要。中红外波长为构建这样的系统提供了许多优势，从低大气衰减到人眼安全操作和抵抗恶劣天气条件。我们展示了一个完整的带间级联系统，用于在4.18 µm波长附近进行高速传输 $4.18\mathrm{\mu }\mathrm{m}$. 激光器和检测器的低功耗与大调制带宽和足够的输出功率相结合，使该技术成为自由空间光通信应用的理想选择。我们的概念验证实验采用射频优化的法布里-珀罗带间级联激光器和基于 II 型 InAs/GaSb 超晶格的带间级联红外光电探测器。系统的带宽估计约为 1.5 GHz。它使我们能够通过开关键控方案实现 12 Gbit/s 的数据速率，通过 4 级脉冲幅度调制方案实现 14 Gbit/s 的数据速率。为了与标准错误代码校正兼容，传统的预处理和后处理提高了传输质量。